第22届国际腐蚀大会

The corrosion of oilfield gathering and transportation systems, as well as wellbores, by hydrogen sulfide significantly impacts the normal production of oilfields and can even lead to serious safety incidents. This type of pipeline corrosion adversely affects the economic viability of oilfields. To investigate the corr osion behavior of gathering and transportation pipelines exposed to hydrogen sulfide, a high - temperature and high -pressure dynamic corrosion reaction kettle was utilized in a controlled indoor environment. Additionally, the study examined the corrosion inhibition performance of a combination of hydrogen sulfide corrosion inhibitors and desulfurizers. The research results indicate that as the partial pressure of hydrogen sulfide increases, the corrosion rate of X65 steel gradually rises. Similarly, an increase in watercut correlates with a gradual increase in the corrosion rate of X65 steel. Furthermore, as the corrosion temperature increases, the corrosion rate of X65 steel initially rises before subsequently decreasing. When employing the H 2S corrosion inhibitor composite desulfurizer system, a synergistic corrosion inhibition effect is observed. This approach demonstrates superior hydrogen sulfide corrosion inhibition compared to the use of a single corrosion inhibitor, with the corrosion inhibition rate of X65 steel potentially increasing by 2 to 10 percentage points.

The present study conducted an in-depth investigation of the electrochemical corrosion behavior and microscopic corrosion mechanisms of X80 steel under a supercritical CO2 (sCO2) environment at 60° C and 9 MPa. Building upon the traditional three-electrode setup, the researchers innovatively designed two novel in -situ electrochemical testing circuits, one under a CO2-enriched environment and the other under a H 2O-enriched environment. Through electrochemical impedance spectroscopy, the study revealed the distinct differences in the interfacial corrosion of X80 steel under the CO 2-enriched and H 2O-enriched environments, which corresponded to the varying corrosion conditions within different regions of the pipeline. Coupled with the analysis of surface evolution, the study provided a detailed elucidation of the deposition and development mechanisms of the corrosion products. Furthermore, the researchers employed micro -scale density functional theory (DFT) calculations to explore the three-step hydrolysis mechanism of sCO2 on the Fe surface and the potential formation pathways of the FeCO3 product, which offered valuable theoretical insights into understanding the corrosion behavior of carbon steel under the supercritical CO2 environment.

The landing section of submarine pipelines is prone to mixed interference from stray currents, exacerbating corrosion issues. The corrosion behavior and prediction methods for corrosion rates under severe pipe -to-soil potential fluctuations remain areas of study. This paper introduces a novel real -time calculation method for interference corrosion rates grounded in the principle of equivalent circuit response under overpotential driving. By analyzing the corrosion kinetics process, it is evident that pipe-to-soil potential fluctuations induce significant non -Faradaic effects, and the characteristics of these fluctuations substantially impact the proportion of non-Faradaic processes, influencing corrosion rates. This calculation method effectively isolates the influence of non -Faradaic processes on corrosion rates, achieving a prediction accuracy exceeding 85%. Furthermore, this approach calculates corrosion rates based on corrosion current, mitigating the influence of objective factors like corrosion factors and environmental temperature and enhancing its applicability. The relevant achievements are of great significance for the comprehensive perception of corrosion.

In the oil and gas industry, the presence of oil/water mixtures is common during transportation pipelines, but which suffers complex corrosion for different water cuts[1-2]. At low water cuts, the average corrosion rate o f steel,wetted by the bulk oil solution and dispersed water -in-oil droplets, is low. Contrarily, at high water cuts, the steel is seriously corroded, due to that it is wetted by the bulk water solution and dispersed oil -in-water droplets. Though, the previ ous research have built a tight relationship between average corrosion rate and wetting phenomenon of steel [3-6], the localized corrosion behaviour, which is mainly attributed to the dispersed oil -in-water or water -in-oil droplets, has not attracted much attention. Consequently, the CO2 corrosion behaviour of X65 carbon steel under water -in-oil droplet and oil -in-water droplet was systematically investigated by a combination of scanning electron microscopy, Raman spectroscopy, NPFLex3D and COMSOL simulatio n in present research. Under the water -in-oil droplet, crystalline FeCO 3 was found, caused by the high concentration of Fe 2+ and CO 32-, according to COMOSL simulation results. Notably, around the oil/water interface, a ridge consisting of compact FeCO 3 was observed, because the precipitation of FeCO3 is accelerated by the short diffusion path of CO2 near the edge of the droplet. Under the oil-in-water droplet, corrosion islands caused by the invasion of water can be found, indicating that small water droplet s emphasised the development of localized corrosion underneath the oil droplet. The novel research findings contribute to further understanding of localized corrosion mechanism of pipeline exposed to oil/water mixture.

Microbiologically influenced cor rosion (MIC) in shale gas field is a major threat with the hydraulic fracturing fluid injected into the subsurface. In this study, the microbiome collected from a shale gas produced water sample was extracted and cultivated in ATCC 1249 medium modified with 10 g/L NaCl anaerobically at 30 ° C. D-amino acids, which were reported as biocide enhancers, were found to enhance 2,2 - dibromo-3-nitrilopropionamide (DBNPA) biocide on the mitigation of shale microbiome MIC on X80 carbon steel. The combination of 50 ppm (w/w) D-leucine + 50 ppm D - alanine + 1 ppm D-tyrosine had the best enhancement effect on 50 ppm DBNPA with 84% less weight loss, and 67% lower corrosion current density (icorr) compared to 50 ppm DBNPA alone. The corrosion data were consistent with the enh anced biofilm inhibition observation. The experimental data also indicated that D-tyrosine used alone at a low dosage of 1 ppm enhanced DBNPA considerably, with 44% less weight loss and 47% less icorr. The electrochemical results showed the positive response of shale gas microbiome biofilm to the injected magnetite nanoparticles indicating the extracellular electron transfer might be a main mechanism for its corrosion.

Aiming at the problem of pipeline external corrosion caused by many factors, such as the existing process of anti -corrosion joint coating operation of oil an d gas pipelines in mountainous areas can not effectively judge whether the foaming is complete, the water inflow of foam insulation layer is serious, and the material acceptance link is relatively lacking, the literature of pipeline external corrosion anti - corrosion joint coating is sorted out, and the formation mechanism of pipeline external corrosion in mountainous areas is discussed. The difficulties and key points of on-site anti-corrosion joint coating operation are summarized, and the anti-corrosion and heat preservation operation methods of mountain gathering and transportation pipelines suitable for the unique pipe -soil coupling, internal and external medium synergy and multi-physical field influence in mountainous areas are explored.

In order to solve the problem of bacterial corrosion caused by oil sludge deposit and water at the bottom of the tanks during the long -term service of crude oil storage tanks, and then improve the emergency respon se capability and transport capability to deal with the sudden supply interruption of crude oil, this paper stud ied the corrosion behaviour and law of different bacteria (SRB, IOB, SRB+IOB) in the crude oil storage tanks in the west of China by the biocult ure technology, weightlessness analysis, electrochemical testing, surface analysis, orthogonal experiments, etc. The corrosion behaviours and laws of steel for storage tanks in the environment of sedimentary water at the tank bottom revealed the growth law s and mechanisms of corrosion of SRB and IOB; the bactericidal enhancement effects of different combinations of D-amino acids, bactericides and bacteria on biofilm colonies on steel surfaces were investigated; the behaviors and mechanisms of different bacteria controlling the corrosion of actual colony through competition in the environment of oil sludge were explored, a variety of anticorrosive microorganisms mixed to control actual colony corrosion in oil and gas fields was evaluated. Finally this study developed D-amino acid-enhanced bactericidal corrosion inhibitor and biological inhibitor products that suitable for oil sludge corrosion at the bottom of the tanks, and formulated an effective bacterial corrosion control strategy of the bottom of the tank sediments, laying the foundation of the long term safety of the crude oil tanks in service.

This work investigated the microbial corrosion behavior of X60 pipeline steel under pipeline oil sludge enriched with field -separated SRB and compared the corrosion inhibitory effects of biocides CTAC and DMTT on X60 steel SRB -MIC in different mediums. Oil sludge possessed corrosive property. The oil sludge medium prevented the escape of H2S from SRB metabolism, which caused acidification of the oil sludge. The number of planktonic and sessile cells in the solution medium increased and then decreased, while the cell counts in the oil sludge medium continued to increase. The corrosion rate of carbon steel in SRB oil sludge was 1.6 times higher than that in SRB solution. The corrosion of the X60 coupons in SRB mediums was mainly localized, with corrosion pits up to 252.6 μm wide and 34.05 μm deep in the SRB oil sludge system. The excellent water-soluble CTAC effectively inhibited the SRB-MIC in solution but had little effect on the SRB-MIC in the oil sludge. The MIC in solution and in oil sludge was inhibited for a long period of time by 100 ppm DMTT. Application of DMTT in pipelines covered by oil sludge may be a new method for long-lasting inhibition of SRB-MIC.

CO2 corrosion is commonly existed in oil and gas field production, which is influenced by various f actors. The film of corrosion and scaling products coated on metal surface has a significant impact on the corrosion behavior. Although numerous studies have been carried out on the CO 2 corrosion product film under various conditions, establishing a correl ation between the microstructure of the corrosion product film and its corrosive behavior remains challenging due to limitations in research methodologies. High-temperature and high -pressure corrosion weight loss experiments were carried out, along with i n-situ electrochemical testing techniques under elevated temperature and pressure conditions, to investigate the CO2 corrosion behavior of N80 steel in varying calcium ion environments. With a comprehensive analysis of the corrosion product film, valuable insights can be obtained regarding the growth mechanism of CO 2 corrosion films under various conditions. Among them, the high - resolution three -dimensional tomographic scanning imaging of product films is achieved by using synchrotron radiation computed lam inography (SRCL) technology to obtain the 3D morphology and porosity distribution of product films. Based on this, a correlation model between the microstructure of CO2 corrosion product films and the corrosion behavior is constructed. This research work h olds significant theoretical value in enhancing the understanding of CO2 corrosion mechanism and under-deposit corrosion behavior, thereby establishing a crucial theoretical foundation for effectively managing CO2 corrosion under intricate operational conditions.

Corrosion of oil tank bott om dramatically threatens safety production of petrochemical industry. Conventional ultrasonic inspection, magnetic flux leakage and other nondestructive testing (NDT) technologies involve time -consuming and labor - intensive production suspension and tank c leaning. Acoustic emission (AE) is an emerging passive NDT approach without interrupting normal operation. But the AE signals are easily interfered by ambient noise. In response, this work aims to improve noise processing and severity determination perform ance of AE technology in detecting oil tank bottom corrosion. An AE inspection platform that consists of vertical oil tank, AE monitoring system and AE analysis software was designed and constructed. To identify the AE sources of ambient noises, time -frequency domain features of AE signals are extracted and a BES -SVM algorithm was proposed. It achieves 95% of accuracy in recognition of seven artificial AE signals in experiments. Moreover, to evaluate the severity of oil tank bottom corrosion, one -dimensional AE signals are converted into two -dimensional mel -spectrum and convolutional neural network (CNN) is employed to handle the mel -spectrum to determine corrosion severity. Experiments shows that over 95% of corrosion in different degrees are successfully identified by the mel spectrum-based CNN model.

This article combines the characteristics of aluminum alloy materials to design a coating formula suitable for the internal coating of aluminum alloy drill pipes. The formula achieves low-temperature curing while retaining the original anti-corrosion performance of the coating, ensuring that the aluminum alloy drill pipe body is not affected. We also conducted research on the low -temperature curing process of the internal coating of aluminum alloy drill pipes, including surface blasting treatment effect, spraying and curing process research, and determined the blasting process, spraying parameters and curing temperature. Type tests were conducted on the internal coating of aluminum alloy drill pipes, including adhesion, chemical corrosion resistance, high temperature resistance, roughness, and wear resistance. The performance of the coating was analyzed, and the tests showed that it has excellent anti-corrosion performance. The inner surface roughness is greatly reduced, which can save 20-30% of drilling power. While protecting the service life of aluminum alloy drill pipes, it also saves water horsepower, meeting the requirements for the u sage of aluminum alloy drill pipes in drilling.

In the actual soil environment, the pipelines are subject to the combined action of SRB and NRB, and will inevitably be affected by stress during service. However, the corrosion mechanism of X80 steel under elastic stress and yield stress with the coexistence of SRB and NRB remains unclear. In addition, the effect of mixed bacteria and stress on the corrosion behavior of X80 steel under traditional cathodic protection, has not been reported. Therefore, we conducted in -depth research on the above-mentioned issues. It was found that in the inoculated environment, microorganisms and yield stress synergistically accelerated the corrosion of X80 steel, and the most serious damage resulted when SRB was involved. SRB and yield stress together led to the formation of secondary pits on the specimen surface. However, if mixed with NRB, the pitting degree of X80 steel surface was weakened, indicating that addition of NRB could inhibit the stress corrosion caused by SRB. After applying cathodic p olarization, pitting pits were still found i n the inoculated group. With the negative shift of the cathodic potential, the uniformity of corrosion damage was reduced, but the pitting was intensified.

The flow accelerated corrosion (FAC) behavior and the inhibition on FAC of X65 steel gradual contraction and gradual expansion pipes under high -pressure conditions were studied by high pressure dynamic in situ electrochemical methods. The FAC rate is reduced along the flowing direction of gradual contraction pipe. However, the FAC rate is firstly decreased and subsequently increased along the gradual expansion pipe. For the inhibition on FAC, there is no noticeable inhibition effect at extremely low inhibitor concentration. The polarization resistance and inhibition efficiency ascend firstly and then decend along the gradual contraction pipe at low inhibitor concentration. Nevertheless, the polarization resistance is generally decreased along the gradual expansion pipe. At higher inhibitor concentration, the polarization resista nce and inhibition efficiency drops overall along the gradual contraction pipe. However, the polarization resistance is enhanced, followed by a fall along the gradual expansion pipe. The FAC rate and inhibition effect at the top of gradual contraction pipe is symmetrical to that at the bottom wall while it is asymmetrical at the top and the bottom of inclination section in gradual expansion pipe. The secondary flow and vortexes is present at gradual expansion pipe while they do not appear at gradual contraction pipe. The distribution of corrosion rate and distinct inhibition effect at different inhibitor concentration are associated with hydrodynamic characteristics at gradual contraction and gradual expansion pipes. The findings could provide theoretical fo undation for the protection of flow accelerated corrosion at gradual contraction and gradual expansion pipes in high CO 2 partial pressure environments.

This presentation will show a stainless steel corrosion -resistant treatment surface (CTS) by modifications of a s.s. surface using chemical and electrochemical methods in situ. Compared with a traditional natural passive film, this method reduces the corrosion rate of the material from 23 g/(m2•h) to below 1 g/(m 2•h) in 6 wt% FeCl 3. A study by XPS shows that CTS film thickness is 100 times thicker than that of a natural passive film. More importantly, the stainless steel surface film treated by CTS technology has also successfully applied to various equipment in refineries for a variety of crude oils, such as packings and internals in the vacuum tower and atmospheric tower. This technology shows excellent corrosion resistance, effectively reducing the corrosion rate and therefore, greatly improves the service life of the materials. Corrosion Rate in FeCl3 317L packing that has been used for 4 years 317L+CTS packing that has been used for 4 years Correspondence to: zhaoxy@candortech.com

Petrochemical industry is the pillar industry of modern industry in China. As the leading device of petroleum refining industry, the equipment integrity of atmospheric distillation unit is of great significance to the safe and stable operation of subsequent process. China's crude oil resources are in short supply, and crude oil imports are large. The processing of low -quality crude oil such as high sulfur, high nitrogen, high acid and chlorine has become the development trend of the industry. As the first production process in the petroleum refining process, the atmospheric and vacuum distillation unit is affected by the processing of inferior crude oil, and the corrosion failure cases in the unit are frequent, which affects the economic benefit s and the life safety of the production personnel. The types of corrosion failure in the atmospheric tower are complex, and it is difficult to form an effective corrosion prediction method. For the corrosion mechanism of the low temperature part of the atmospheric tower top system, such as the prediction and protection of ammonium salt corrosion and dew point corrosion, it has become the focus of research. In this paper, the risk prediction and corrosion mechanism of ammonium salt corrosion and dew point corrosion at the top of atmospheric tower are studied. The failure evolution law based on flow corrosion and the corrosion protection measures and intelligent prevention and control measures of the overhead system of atmospheric tower are introduced. The diagnosis process and prevention and control measures for identifying the risk of flow corrosion are proposed. It provides theoretical guidance for the study of crystallization corrosion mechanism and dew point corrosion mechanism of low temperature ammonium salt at the top of atmospheric tower and the prediction of intelligent corrosion protection.

Hydrogen (H2) pipeline systems are fundamentally the same as natural gas pipeline networks, but face a more serious safety challenge due to potential hydrogen embrittlement (HE) risk. At present, H 2 transportation and storage are intentionally operated under high -pressure (HP) conditions ( i.e., 5-20 MPa for tra nsportation, 35- 100 MPa for storage), which make H2 under supercritical state (i.e., supercritical H2, s-H2). In this study, the thermodynamics of H 2 at a wide combination of temperatures (300 - 900 K) and pressures (0.1 - 100 MPa) has firstly been establi shed based on a lattice-molecule model for predicting the adsorption and dissociation of gaseous and supercritical H2 on the Fe-based steel surface. The configurations of H2 adsorption and dissociation on Fe (100) and Fe 2O3 (001) surfaces were investigated through the density functional theory (DFT) calculation, and the corresponding mechanism was elucidated using hybrid orbital theory. By applying the combination of DFT calculation and statistical thermodynamics, the dissociative adsorption of HP H 2 on Fe (100) and Fe2O3 (001) surfaces upon varying temperature and pressure was predicted and the results well aligned with previously published experimental studies. Compared to the gaseous H2, s-H2 was likely to be more active on the iron (Fe) and its oxide (Fe 2O3) surface in terms of dissociating into H atoms and could cause steels more susceptible to HE. The results also confirmed that the presence of the Fe 2O3 scale could protect pipeline steels from environmental hydrogen permeation under the investigated HP conditions.

Hydrogen energy plays a key role in the energy revolution. An effective and practical method for delivering hydrogen energy at a reasonable cost is to blend hydrogen into the existing natural gas pipelines. Internal corrosion is inevitable for the in-service natural gas pipelines, which typically results in the formation of corrosion product scale on the steel surface. Significant effects on hydrogen permeability and compatibility c an result from the corrosion product scale after hydrogen has been blended. However, the impact of the corrosion product scale on gaseous hydrogen adsorption and diffusion remains unclear. This study provides an experimental method for corrosion product sc ale preparation and gaseous hydrogen permeation [1] in the hydrogen blended natural gas environments. The hydrogen permeation kinetics of pipeline steel in the presence of corrosion product scale was studied. Additionally, density functional theory (DFT) an d molecular dynamics (MD) techniques were used to study the hydrogen adsorption mechanism on Fe and iron carbonate (FeCO 3) surfaces. It was suggested that the presence of FeCO 3 scales considerably reduced the stable hydrogen permeation flux, effective hydr ogen diffusion coefficient, and effective subsurface hydrogen concentration. The suppression of hydrogen permeation into the steel substrate is caused by the surface adsorption effect and structure blocking impact of the FeCO3 scales. This suggests that the corrosion product scale can be used as hydrogen barriers in gaseous hydrogen environments.

Given the risks of casing corrosion failure and CO 2 leakage at the casing -cement interface in CO 2 sequestration technology, along with the limited purity of carbon sources and the unclear corrosion mechanisms and crevice corrosion sensitivity of L80-13Cr in this system, this study investigate d the corrosion behavior and crevice corrosion sensitivity of L80 -13Cr in a simulated cement pore solution environment containing impurities (SO2, NO2, O2) at 10 MPa and 80° C. The results indicated that, in the absence of crevice structures, carbon source impurities had no significant impact on corrosion behavior of L80 -13Cr steel, with a very low uniform corrosion rate. The surface of t he samples was predominantly covered by protective Cr -containing products.. However, notable pitting behavior is observed. In the presence of crevice structures, localized corrosion occurred within the crevice. Additionally, pitting was more pronounced tha n in the absence of crevices. Besides Cr -containing products, FeCO3 was also formed within the crevice. The introduction of different concentrations of impurity gases did not significantly alter the crevice corrosion behavior, which may be related to the C a2+-rich environment and the interactions between the impurity gases. The destabilization and failure of the passivation film within the crevice pose a potential risk of crevice corrosion failure and CO2 leakage for L80-13Cr in this system.

Pitting corrosion is one of the threatening causes of failure faced by in-service pipeline steel. The pipelines may pass magnetic fields generated by various electromagnetic devices and electricity transmission lines. The magnetic fields may affect the pitting corrosion of pipeline steel. To study the effect of a magnetic field on the pit initiation and evolution of pipeline steel, this paper investigates the critical pitting potential of X70 pipeline steel in 0.02 mol/L Na 2CO3+0.001 mol/L NaCl solution and the effect of a 0.1 T magnetic field on pitting corrosion evolution. The potentiodynamic polarization curves and potentiostatic polarization testing methods have been used, combined with surface morphology measurements. The conclusions of the study include: (1) When the polarization potential is in the range of 0.30~0.80 V SCE, the evolution of pitting corrosion undergoes a process from initiation and growth at the edges to simultaneous initiation and growth at the edge and center. When the potential is higher than 0.50 VSCE, pitting corrosion occurs along with oxygen evolution reaction. (2) The critical pitting potential of X70 steel is located in the range of 0.25 -0.30 VSCE. (3) The results of potentiostatic polarization and surface morphology show that the electrode is in a passive state at 0.20 VSCE and 0.25 VSCE without a magnetic field, and a 0.1 T magnetic field promotes the initiation of pitting corrosion. The magnetic field shows the effect of transforming the electrode from a pre -passive state to an active dissolved state. The effects of magnetic fields on pitting corrosion are rationalized by the interfacial mass -transport kinetics modulated macro - and micro - magnetohydrodynamic effects.

As an important place for the production, storage and transportation of LNG, LNG liquefaction plant has a series of strict treatment methods and technological processes. In order to ensure the effect and quality of natural gas lique faction, it is necessary to remove impurities such as CO2, Hg and H2S and free water in the purification process. In this regard, effective anti -corrosion measures and scientific management methods can improve the purification effect of natural gas. The re sults show that: (1) the degree of corrosion has a great impact on the safety performance of the equipment pipeline, especially the corrosion at the elbow is easy to cause natural gas leakage, and then cause accidents; (2) Changes in pressure, temperature and flow rate are also factors affecting corrosion in the purification process of LNG liquefaction plant; (3) Specific measures can be started from the analysis and treatment of corrosion sites and corrosion types of important devices; (4) The construction and training of professional skilled personnel is conducive to the research and development of corrosion science and anti -corrosion engineering. Through the above discussion, it is concluded that the upgrading and application of corrosion and protection technology can help the smooth and efficient operation of LNG liquefaction plants, extend the service life of equipment and facilities, and accelerate the construction of talent teams, thus promoting the high -quality development of LNG industry.

Carbon capture, utili zation, and storage (CCUS) technology has been considered for reducing CO 2 emissions and improving energy efficiency. However, during the capture process, impurities such as O 2, SO2, and NO 2 are present, which accelerate corrosion of transportation pipelin es and wells. Nevertheless, researches also found several interesting corrosion inhibition phenomena in the system. In this study, we summarized the spontaneous corrosion inhibition phenomena during the capture, transportation process, and outlined the corresponding inhibition mechanisms. These include the corrosion inhibition mechanisms of the degradation products of organic amines, inhibition behavior of SO 2 on CO2 corrosion processes. Additionally, this study also proposed several corrosion inhibition me thods in CCUS system. Understanding these corrosion inhibition mechanisms is crucial for corrosion control of CCUS facilities.

With the development of oil and gas resources, the formation water with high concentrations of Ca2+ and Cl− has put forward higher requirements for the safe service of tubular columns. In this study paper, the underground environment is simulated using high-temperature and high-pressure autoclave; electrochemical research results are combined; and the effects of Ca 2+ concentration, corrosion temperature, and corrosion time on the corrosion behavior of P110 steel in CO 2- saturation solution are analyzed. Research results show that the presence of Ca2+ promotes the acidification of the solution and accelerate the dissolution of the P110 steel. The trend of corrosion rate and Ca 2+ concentration in high-Cl-solution is a “V” curve. The highest corrosion rate of 2.2 mm/a occurs in 1080 mg/L Ca 2+ CO2-saturated NaCl solution. As the temperature increases, the corrosion rate of P110 steel decreases. The corrosion rate is approximately at a constant value above 120 ° C. In addition, higher Ca2+concentration in the solution increases the probability of pitting for P110 steel. For FexCa1-xCO3 compounds, no strict ratio is observed between Fe and Ca, and the shape of the product depends on the concentration of Ca2+ ions in the solution.

In order to further explore the effect of hydrogen permeation on the performance of pipeline inner coating, electrochemic al hydrogen permeation method was used to study the hydrogen resistance of liquid epoxy coatings. visual inspection and three -dimensional ultra -depth microscope were used to observe the effect of hydrogen charging on the surface morphology of coatings, and the pulling method was used to test the adhesion of coatings. and the hydrogen permeation and permeability coefficient of coating were tested by differential pressure method. The results show that the hydrogen diffusion coefficient of coated steel is much greater than that of bare steel, indicating that the coating can improve the hydrogen resistance of steel. However, with the progress of electrochemical hydrogen charging, obvious bubbling appeared on the surface of coating, and as the hydrogen charging time increased, the bubbling became more serious, the coating/steel interface was destroyed, and the adhesion of coating was significantly reduced. The hydrogen permeation and permeability of the coating were obtained by differential pressure method.

The corrosion issue of metal materials employed in oil and gas fields is becoming more and more prominent. Based on the detailed analysis of the corrosion mechanism of metal materials, an idea of surface homogenization was proposed to improve the corrosion resistance of pipes, i.e., homogeneous corrosion c oating fabricated by using the surface technology. In the term of the stress corrosion cracking of martensitic stainless steel induced by the pitting corrosion, the surface active inclusions of super 13Cr martensitic stainless steel (S13CrMSS) were elimina ted, the high energy area was significantly reduced by changing the compositions of the passivation solution and improving the pre -passivation process. Accordingly, a nano - scale amorphous film was preformed on S13CrMSS surface, which improved the pitting potential of S13CrMSS by about 100%. In the term of the carbon steel, corrosion resistant homogeneous coatings were prepared on its surface by thermal spraying and laser cladding. Plasma spraying coating significantly improved the corrosion resistance of the metal pipes, but the issue of connectivity porosity leaded to the corrosive medium easy to penetrate into the surface of the matrix, inducing the matrix corrosion. The porosity of coating fabricated by the high velocity oxygen flame spraying (HVOF) and laser cladding was significantly lower than that of the plasma -sprayed coating. There was commonly no connectivity pore in the coatings, which effectively controlled the active corrosion area on the surface of the metal pipes. Therefore, based on the idea of surface homogenization, the corrosion resistance of metal materials can be significantly improved.

CCUS pilot tests are carried out in several deep oil reservoirs over 3000m depth in the region of North China. In the oil production process, the temperature and pressure is high, and the CO 2 phase will change from supercritical to gaseous sta te, which leads to the complex corrosion mechanism. This article will investigate the corrosion behavior under different CO 2 phase environments, providing a basis for the design of anti -corrosion measures. Weight loss method is employed to study the corrosion rate of N80 carbon steel in different CO 2 partial pressure. Subsequently, techniques such as SEM, EDS, XPS, and Raman spectroscopy are used to study the morphology and composition of the corrosion products. The results show that when the temperature is 80°C, within the CO 2 partial pressure range of 0.4~18 MPa, the average corrosion rate of N80 steel varies from 0.1916mm/a to 0.8191 mm/a, and exhibits a trend of initially increasing, followed by decreasing, and then increasing again, with the peak under the condition of 10.5 MPa. The corrosion product film forms double-layer compound film structure by the deposition of crystalline FeCO3 particles, and the corrosion morphology exhibits typical uniform corrosion. In order to enhance the long-term safe production of the wellbore, a combined casing design is proposed, utilizing of 13Cr stainless steel from 50m above the top boundary of the target interval to the bottom hole, N80 carbon steel for the rest casing. The anti-corrosion method for the tubing is recommended of N80 carbon steel with corrosion inhibitor injection. The anti-corrosion plan has been successfully implemented in an oilfield of North China. This article clarifies the corrosion behavior and morphology of N80 carbon steel under different CO2 phase state, providing reference for CO2 flooding anti-corrosion design.

The effect of hydrogen on passive film and corrosion behaviour of 2507 super duplex stainless steel (SDSS) in H 2S environment was studied by electrochemical experiments and ToF -SIMS characterization. The results showed that sulfides were present in the passive film in the forms of FeSx and NiSx, and they were enriched in local passive film of the austenite phase since austenite was rich in Fe and Ni elements. In H2S-containing environments, the passive films had a bilayer structure. The inner layer was compose d of oxides of Cr and Ni, while the outer layer was enriched in oxides of Fe and Mo, hydroxides and sulfides. Moreover,hydrogen thickened the passive film, and induced the formation of hydroxides and sulfides in the passive film, which resulting in the dec rease in pitting resistance. Due to the better corrosion resistance of the austenite phase, pitting occurred at the ferrite phase and phase boundary.

Rare earth elements have a significant impact on the mechanical properties of microalloyed steels, including hydrogen embrittlement resistance. This study investigates the mechanism by which rare earths affect the hydrogen embrittlement sensitivity of 4130X steel using electrochemical hydrogen permeation, thermal desorption, slow strain rate tensile testing, EBSD characterization of fracture microstructures, and TEM characterization of carbides. After adding rare earth elements (La+Ce content of approximately 0.04 wt.%), the hydrogen embrittlement sensitivity significantly decreases, with the hydrogen diffusion coefficient reducing from 1.19× 10-6 cm2s-1 to 0.86× 10-6 cm2s-1. The saturated hydrogen concentration and hydrogen trap density increase from 2.78× 10-6 mol· cm-3 and 5.92× 1019 cm-3 to 5.92× 1019 cm-3 and 9.82× 1019 cm-3, respectively. The increase in hydrogen trap density is mainly attributed to the increased proportion of high-angle grain boundaries and the changes in the type, morphology, and distribution of carbide precipitates in the steel. Regarding the hydrogen embrittlement suppression mechanism, rare earth elements reduce the size of the original austenite grains and bainitic laths, enhancing the crack propagation resistance of the steel matrix. More importantly, rare earths promote the dispersion of nanoscale spherical M3C carbides within the bainitic laths and inhibit the formation of long strip-shaped M7C3 carbides, thereby weakening the accumulation of hydrogen at grain boundaries and reducing the hydrogen embrittlement sensitivity of the steel.

This study investigates the corrosion behavior of six types of Q345 low-alloy steel in chloride -containing environments to explore the relationship between microalloying element content and electrochemical characteristics. NaCl solutions with concentrations of 0.01M, 0.1M, 1M, and saturated were used to simulate refinery and chemical process corrosion conditions. The polished steel samples were immersed for durations of 50 hours, followed by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests. The results reveal that during the early stages of corrosion, microalloying elements have impact on the anodic p rocess, dominated by iron dissolution. However, the cathodic behavior is significantly influenced by microalloying elements, particularly as NaCl concentration increases. Spearman correlation analysis between the alloying elements (Mn, Nb, Cr, Ti, Zr, N, P, S, Cu, Ni) and electrochemical parameters (corrosion potential and current, charge transfer resistance) demonstrated that elements such as Mn, Nb, Cr, Ti, Zr, and N enhance corrosion resistance, while P and S negatively affect it. These findings provide insights into the optimization of microalloying elements for developing more corrosion-resistant low-alloy steels in industrial applications.

The corrosion behavior of a Newly Ni -based superalloy was studied in environments of synthetic coal -ash and synthetic flue -gas at 650 ° C and 700 ° C for 500h comparatively. The corrosion kinetics, morphologies, compositions and phases of the corrosion products were characterized by means of SEM, EDS, and XRD, respectively. The results indicated that the temperature is acritical factor in the formation of corrosion layer for the newly Ni -based superalloy. The common denominator is that a dense and uniform layered oxide scales consisting of a Fe 2O3 outer layer and an Cr2O3 and Al2O3 inner layer were observed at both 650 o Cand 700 o C. The 700 ° C high-temperature is the primary cause of the formation of the convex corrosion products and internal sulfide MxSy (M: Cr, Mo). The corrosion mechanism of the newly Ni-based superalloy was also discussed based on the experimental results.

The corrosion behavior of Inconel alloy 740H in simulated Coal-Ash / Flue-Gas Environment was investigated with high temperature corrosion test for 500h at 850° C. The weighing method, SEM (Scanning Electron Microscope), EDS (Energy Dispersive Spectrometer) and XRD (X -Ray Diffraction) analyse s were employed to understand the corrosion kinetics, morphologies, compositions and phases of the corrosion products, respectively.The results indicated that the mass gain of Inconel alloy 740 H was an approximately stable up to 500h. After corrosion for 1 00h, a continuous oxide scale identified as Cr2O3 and MnCr2O4 spinel formed on the surface of Inconel alloy 740H. Below the oxide scale, Cr depletion region was found and a large amount of inner corrosion products Al 2O3 and Ti-rich were also observed. Afte r corrosion for 500h, the thickness of oxide scale and the corrosion depth increased obviously with the corrosion time increasing. The inner corrosion products was composed of Al2O3, Cr2O3, MoS and Ti-rich and distributed along the grain boundary. The corr osion mechanism of Inconel alloy 740 H was also discussed based on the experimental results.

This study investigated the impact of cold deformation reduction on the corrosion behavior of Zr50Ti25Nb25 alloys in a simulated proton exchange membrane water electrolysis environment. The result indicated that cold deformation did not alter the phase structure of alloys, but increased dislocation density proportional to the deformation degree. The geometrically necessary dislocations reached approximately 1.194× 1016 m−2 at a 70% cold deformation reduction. The presence of high -density low-angle grain boundaries within heavily deformed grains suggested incomplete recrystallization. Electrochemical tests confirmed that cold deformation negatively affected the corrosion resistance of Zr 50Ti25Nb25 alloys in th e simulated proton exchange membrane water electrolysis environment. At a maximum reduction in cold deformation, the passive current density was about 2.971 × 10 −5 A/cm2. The donor concentration of the passive films behaved as n -type were on the order of 10 20 cm−3 and increased with the enhancement of cold deformation reduction. X -ray photoelectron spectroscopy analysis indicated that the reduced resistance of the passive film to corrosion could be attributed to a decrease in oxide content, particularly ZrO2, which fell below 50% after deformation. Cold deformation increased dislocation density, creating potential initiation sites for pitting corrosion. This height ened dislocation density hindered the formation of a stable passive film, resulting in diminished corrosion resistance.

The effect of electrochemical hydrogen charging on the corrosion behavior of the AlNbTiZr high entropy alloy in a 0.5 M H 2SO4 solution was investigated. The results revealed localized corrosion and cracks occurring after 120 h of charging, with failure analysis indicati ng transgranular cracking. Moreover, both the corrosion and passive current densities exhibited an increase with prolonged charging time from 0 h to 120 h. XPS analysis showed that the ratio of OH − to O 2− within the passive film increased from 0.379 to 0.8 54 as the time extended to 120 h. This observation suggested that hydrogenation diminished the alloys’ corrosion resistance.

at the same system. The production fluids among the different formations and the injection water of the water flooding model with the formati on water are seriously incompatible. The mixed transportation mode of surface production leads to a high proportion of scaling in the wellbore and gathering station ( ≥ 50 % ). The pipelines and equipments of nearly a thousand stations need high concentrat ion scale inhibitor and frequently scale removing service. For example a major oilfield has spent an annual investment of 100 million yuan in scale comprehensive prevention and removing. Those has become a long-term direction for improving quality and efficiency. According to the working tenets of 'prevention first, prevention and control combination', a complex scale prevention and controlling technology system combining physical and chemical methods, such as new kinds scale inhibitor, centralized scale forming device and inner coating et al. , has been formed in the scale control demonstration area. It has been popularized and applied in 158 stations of production plants in the oilfield, and the overall application effect is remarkable. The research on t he scale inhibitors for high content of barium/strontium scale needs to be carried out in future: 1. the mechanism of the effect of high Fe 2+ content production water on the scale inhibitor; 2.special scale inhibitors with high stability of salt tolerance et al. ; 3. Indoor and on -site scaling dynamic monitoring and evaluation methods; 4. Research on relevant recommendation standards.

In this paper, 2205/X65 clad plate was joined by explosive welding. The clad plate would be used in the oil and gas transmission pipeline to replace the 2205 materials. After explosive welding, the microstructure and the composition of the clad were characterized using optical microscopy, scanning electron microscopy. Properties were inspected by using tensile test, shearing test, microhardness test and Intergranular corrosion test. The examination results showed t he interface of the 2205/X65 alloy plate was typical wavy shape. And No pore, crack or melting zone was inspected in the interface. Tensile test results showed that the ultimate tensile strength, yield strength and elongation of the clad plate were 544MPa, 340MPa, 33%, respectively. The shearing strength average value was about 283 MPa. These mechanical properties r esults reach to the requirement of ASTM A264 -2003 specification. And i ntergranular corrosion test showed that surface of the clad plate was smooth. It meets the requirement of the ASTM A262 -2003 specification practice E. It indicated that the corrosion resistance of the clad plate was better than Mg alloy sheet. Above results indicate that 2205/X65 clad plate joined by explosive could be used in the oil and gas transmission field.

Facing the severe ene rgy shortage and environmental problems, the development of green and low-carbon energy is imminent. Hydrogen energy which has advantages of abundance and long distance transportation is viewed as an important way for the energy transition. The cost of hyd rogen transport through existing natural gas pipeline is low, but hydrogen can penetrate into the pipeline steel and cause damage to mechanical properties of pipeline steel. Microstructure is an important factor affecting hydrogen diffusion in pipeline ste els. Due to the different stress and heat conditions, the surface and internal microstructure of the rolled pipeline steels is different. The ferrite grain size in surface layer of X42 pipeline steel is smaller than other locations, while the surface layer of X52 pipeline steel has continuous banded ferrite/pearlite structure and grains with uneven size. Besides, the residual strain in central layer of X42 pipeline steel is larger than that in surface layer, while the residual strain in surface layer of X52 pipeline steel is larger. Hydrogen permeation behavior is investigated at different positions in the normal direction of X42 and X52 pipeline steels using the electrochemical hydrogen permeation technique. The results show that the values of the effective diffusion coefficient of surface layer in X42 and X52 pipeline steels are the smallest, while the values of the subsurface hydrogen concentration at steady state are the largest. This is attributed to the fact that grain boundaries and continuous banded f errite/pearlite structure hinder hydrogen diffusion [1]. Hydrogen microprint experiment results indicate hydrogen atoms mainly escaped at pearlite, ferrite grain boundaries and near inclusions in X42 and X52 pipeline steels.

Industrial pipelines, crucial for transporting oil and natural gas, are susceptible to hydrogen -induced failures due to hydrogen ingress and local stress concentration[1]. Understanding hydrogen's role in pipeline steel under various stress-strain conditions is essential. This study investigated hydrogen permeation kinetics in X80 pipeline steel under different stress -strain conditions using Devanathan - Stachurski (DS) cell experiments and DFT calculations [2]. Results showed that the increased stress slightly raises the diffusion coefficient meanwhile significantly boosts subsurface hydrogen concentration. Shall ow hydrogen traps formed under plastic deformation hindered hydrogen permeation. Both in situ synchrotron radiation characterization during tensile process and TDS tests confirmed that the shallow hydrogen traps correspond to dislocations in the microstructure. The study established relationship between stress and subsurface hydrogen concentration as well as the correlation between plastic deformation and trap density in X80 steel. As a result, hydrogen permeation kinetics model for X80 steel under stress c ondition was developed. Numerical simulation of a notched DS hydrogen permeation sample highlights the effect of local stress concentration on hydrogen permeation.

The potential for Deep coalbed methane development in the Linfen area is substantial. During the development process, oil pipes are typically used for gas well production. Howeve r, prolonged corrosion resulting from the high mineralization of formation water renders these oil pipes susceptible to perforation issues, significantly hindering the advancement of deep coal -bed gas extraction. Both domestic and international academic communities have conducted extensive research on wellbore corrosion, there remains a paucity of studies specifically addressing corrosion in deep coal seam gas wells. In order to elucidate the corrosion mechanism of the oil pipeline in Linfen deep coalbed me thane well, the formation water and gas producing components were analyzed by chromatography. The micromorphology and mineral composition of the products were studied by scanning electron microscopy and X -ray diffraction. By combining the experimental resu lts with the inherent characteristics of underground conditions, the corrosion mechanism of deep coal seam and the main control factors affecting wellbore integrity are further discussed. The results indicate that: (1) The oil pipe corrosion of deep coalbed methane Wells in Linfen block is mainly electrochemical corrosion and scale corrosion. (2) The high salinity and high content of carbon dioxide in the water quality of the formation are the main factors causing corrosion. (3) The high intensity drainage and production of the rod pump further aggravate the corrosion rate of the tubing.

With the rapid growth and widespread adoption of photovoltaic (PV) power generation, the intersection and parallel proximity between photovoltaic modules, power lines, and pipeline systems have becomed increasingly prominent, leading to AC or DC interference challenges for pipeline systems. This study aims to explore the electromagnetic interference mechanisms exerted by PV power generation systems on pipeline systems. Numerical simulations were employed to investigate the patterns of electromagnetic interference from PV systems on nearby pipelines. In the instance of a 160 MW PV power plant, the interference risks to pipelines were assessed. The research results show that the leakage current of photovoltaic modules has less DC interference on pipelines. The steady -state electromagnetic coupling interference intensity of buried cables and overhead lines of the PV power generation system on pipelines is influenced by multiple factors,including the phase current imbalance degree, phase current size, parallel length, and parallel distance. The risk of pipelines caused by single-phase fault current and lightning current decreases as the scale of the grounding body increases,the safe distance between pipelines and grounding bodies must exceed the continuous arc distance of lightning current. In the actual case, the DC potential deviation of the pipeline caused by a 160MW photovoltaic power plant was less than 5mV, while the maximum AC interference current density of the pipeline reached 67A/m2.

The research aimed to reveal the mechanisms that influence sulfide stress corrosion cracking and establish the correlation between microstructure of the fusion boundary region. Research found that Island -like martensitic structures formed at the fusion interface of X80/Inconel 625 dissimilar welding joints by tungsten inert gas welding (TIG). The significant orientation difference and poor deformation coordination between martensite and austenite interfaces can result in hydrogen accumulation at the phase interfaces, which significantly increases the susceptibility to cracking. In contrast, low heat input cold metal transfer (CMT) welding optimized the microstructure of the heat-affected zone and fusion interface, mitigating the generation of brittle hard phases and improving the SSCC resistance of the welding joints. The tempering effect occurring in the overlap region help to transform the heat -affected zone into a microstructure comprising granular bainite and acicular ferrite, while inverse austenite formed at the fusion interface. This adaptation increased the number of effective hydrogen traps in the weld and further reduced susceptibility to cracking. Heat treatment of the heat -affected zone resulted in a predominantly fine ferrite microstructure, preventing SSCC in the welding joint. Similarly, appropriate post -weld heat treatment improved the SSCC resistance of the TIG weld joint. Furthermore, long-term heat treatment induced nucleation of inverse austenite at the low -energy boundary of martensite, leading to the plate -like morphology that could remain stable at room temperature and effectively reduced SSCC susceptibility.

The production -well tube string in underground coal gasification (UCG) transports mixed coal gas and suffers corrosion due to high-temperature CO2, H2S and water vapor. Corrosion tests of 9Cr and 13Cr materials in simulated UCG environments between 150°C and 300°C were carried out by a high temperature and high pressure autoclave equipment. The effects of gas partial pressure and temperature on the corrosion of the two materials were compared and analyzed. , and material selection suggestions were provided. The results show that the most important factor affecting the corrosion of well tubing is temperature, followed by CO 2 partial pressure. As the temperature increases from 150°C to 300°C, the corrosion rates of both materials first increase and then decrease. When CO 2 partial pressure is 3 MPa, corrosion rates of 9Cr and 13Cr materials reach the maximum at 250 °C, which are 1.620 mm/a and 0.7284 mm/a respectively. Microscopic results obtained by Scanning electron microscopy (SEM) show that corrosion films of 9Cr material are porous and relatively thick, while those of 13Cr material are dense and intact. It is recommended that 9Cr tubes should be used at temperatures below 150°C,and 13Cr tubes should be used at temperatures below 200°C.

Under the guidance of the "dual carbon" strategy, CCUS technology has been widely applied in the field of oil and gas development. CO 2 displacement technology, as one of the main CCUS technologies, has also been widely applied in the field of Oil and gas stimulation. However, in CO2 environment, there are serious corrosion problems with downhole tubing strings. In t his article, pre-anticorrosion working fluid system for oil displacing by CO 2 is introduced to suppress the corrosion of downhole tubing during oil displacing.Through designing the molecular structure and optimizing the synthesis conditions, imidazoline groups and n -SiO2 were simultaneously introduced into the PSI ring opening reaction. Then the composite of inorganic nanoparticles and organic po lymer segments is made as the main agent. The main agent is finally compounded with selected small molecule corrosion inhibitor to produce pre-anticorrosion working fluid. Indoor simulated field experiments show that the system has excellent anti -corrosion performance in environment with large temperature differences an d high CO 2 flow rates. The effective period is over 30 days.Under the continuous working conditions of inflation -sealing-depressurization, the average corrosion inhibition rate is 91.17%, and the pitting corrosion inhibition rate is 86.96%.

The service li fe of onshore oil fields ha s successively entered the middle and later stages, with a decrease in oil well production and a gradual increase in comprehensive water content. One of the prominent issues is that corrosion and leakage caused by hydrogen sulfid e occur frequently in oil wells with no H2S in the early stage of production. It makes the subsequent water reinjection treatment and production more difficult, and increases the cost of reinjected water treatment. In this article, research is conducted on sulfur-containing produced water analysis, SRB, corrosion rate measure, a s well as the related experiment s. T he process flow is optimized, and the multifunctional sulfur removal agent product as well as the matching specialized processing equipment are developed. After desulfurization, deoxygenation, and pH adjustment, the water quality has SRB ≤ 10 2, oil content ≤ 20mg/L, and suspended solids ≤ 10mg/L, meeting the water quality standards for oilfield reinjection water.

This paper explores the hydrogen embrittlement sensitivity of pipeline steel under different hydrogen partial pressures to provide data support for the safe operation of natural gas hydrogen pipelines. The hydrogen embrittlement sensitivity of X60 pipeline steel parent material and girth weld under different hydrogen partial pressure environments was studied. Slow strain rate tensile and in -situ gas phase hydrogen permeation tests were carried out at different hydrogen pa rtial pressures of 10%, 20%, and 30% (total pressure 12MPa). According to the tensile curve and fracture morphology, it is shown that with the increase of hydrogen partial pressure, the mechanical properties of the parent material and girth weld gradually decrease, and the hydrogen embrittlement sensitivity increases. Due to the presence of a coarse-grained Widmanstatten structure, the hydrogen embrittlement sensitivity of the girth weld is much higher than that of the parent material. When the hydrogen par tial pressure reaches 30%, the hydrogen embrittlement sensitivity of the girth weld reaches 27.3%, which is twice as high as the parent material. With the increase of hydrogen partial pressure, the time for hydrogen diffusion in the girth weld to reach a steady state is faster, the steady -state current density is higher, and the apparent hydrogen diffusion rate is higher, which further shows that the hydrogen embrittlement sensitivity at the girth weld is higher than that of the parent material.

With the continuous rise in energy demand, pipeline s will play an indispensable role as the primary transportation medium for oil and gas resources for a long time to come. However, the complexity of the pipeline operating environment makes corrosion prevention a top priority for ensuring pipeline safety. As a primary external anti-corrosion layer for pipelines, three-layer polyethylene (3PE) experiences aging during long -term service, which weakens its corrosion resistance. This article examines the variations in electrical strength of three -layer polyethylene (3PE) and epoxy powder coatings (FBE) under dry and humid heat aging conditions. The experimental findings reveal that aging markedly decreases the electrical strength of both 3PE and FBE, with humid heat aging proving to be more detrimental to the materials. Additionally, infrared spectroscopy analysis shows that the aging process has a minimal impact on chemical groups such as epoxy rings and carbonyls in FBE. In contrast, aging has a pronounced effect on the structure and properties of 3PE materials. Coating thickness has a significant impact on the electrical strength of FBE; with increasing epoxy layer thickness, the electrical strength progressively diminishes. The decline is more gradual within the thickness range of 450 to 550 μm. This research provides valuable insights for the design and development of anti -corrosion coatings for pipelines. It holds significant implications for maintaining the safety of long -term pipeline operations in complex environments.

The integrity of well casings is crucial for safe oil extraction, especially in CO2-rich environments. BG140V steel, a low-alloy steel commonly used in oil fields, faces significant corrosion challenges, particularly in regions like Xinjiang. Understanding how temperature affects the corrosion behavior of BG140V steel in these conditions is essential for optimizing its performance and ensuring the longevity and reliability of oil extraction operations. The effect of temperature on the corrosion rate of BG140V steel in CO 2-containing environment was studied by using the high - temperature and high -pressure reactor by weight -loss method, and the corrosion morphology and corresponding corrosion products of BG140V steel at different temperatures were analyzed by scanning electron microscopy, energy spectroscopy and X -ray photo-electron spectroscopy. The results show that with th e increase of temperature, the corrosion rate of BG140V steel in CO2-containing environment shows a trend of first decreasing and then increasing, and the corrosion rate is greater than 0.076mm/a. The corrosion rate is 0.7501 mm/a at 30 °C, 0.087 mm/a at 90 °C, and 0.2086mm/a at 110 °C. As the temperature rises from 30 ° C to 90 °C, the corrosion products on the surface of BG140V steel gradually become denser, and the regular hexahedral crystals gradually become rounded, and the porosity between the grains becomes smaller, which effectively prevents the corrosion medium from reaching the matrix through the corrosion product film, and the corrosion rate decreases. When the temperature reaches 110°C, the local corrosion products fall off, the film density of the corrosion products decreases, and the corrosion rate increases. When the temperature rises from 30 °C to 90°C, the corrosion products of BG140V steel are basically the same, which are mainly composed of FeCO 3 and (Fe,Ca)CO 3 double salts and amorphous Cr(OH)3 and Cr2O3.

As an important infrastructure for oil and gas energy transmission, the safety and reliability of pipelines are very important for modern industrial systems. Corrosion is one of the main factors affecting the safe operation of pipelines throughout their service lifecycle, so effective corrosion management is the key to ensuring pipeline integrity. With the development of various monitoring and surveying technologies and the improvement of corrosion management standards, pipelines have accumulated a large amount of corrosion -related monitoring and surveying data, and operation and maintenance records as the increase of service cycle, including cathodic protection data, corrosion data, s oil data, interference data, repair records, retrofitting records, etc. The diversity and complexity of these data pose challenges to the integration and mining analysis. The purpose of this paper is to explore the comprehensive data fusion and analysis me thods of pipeline corrosion protection, and to propose a set of systematic data storage, cleaning processing, spatiotemporal alignment and mining analysis processes by discussing the problems faced at the data level, analysis level and management level. Th is paper first analyzes the types and characteristics of pipeline corrosion -related data, then proposes a series of methods such as data preprocessing, data fusion, correlation analysis and data application, and finally discusses the application value and potential challenges of these methods in actual pipeline corrosion management scenarios. The results show that through comprehensive data fusion and scientific analysis, the efficiency and accuracy of pipeline corrosion management can be improved in cost -effective way, and scientific decision-making support can be provided for the safe operation of pipelines.

The precipitation of elemental sulfur in CO2 transport pipelines may affect the corrosion mechanism of pipeline materials in supercritical CO 2 environments. This study investigated the corrosion mechanism of X80 pipeline steel in a water -saturated supercritical CO2-rich phase under dynamic conditions at 40° C and 8 MPa. The results indicated that the general corrosion rate was high both with and without sulfur, and increased with flow rate. However, the pitting factor showed a decreasing trend. At a rotational speed of 900 rpm, the pitting factor in the sulfur -containing condition was less than 5, suggesting that significant pitting corrosion may not occur. This conclusion was further supported by 3D surface morphology analysis. The increase in corrosion rate was related to enhanced mass transfer of the corrosive medium due to flow, while the reduction in pitting tendency may be attributed to decreased contact time between elemental sulfur particles and the metal substrate, reducing the likelihood of under - deposit corrosion. Scanning electron microscope (SEM) results showed that the corrosion produ ct films were loose and porous, providing limited protection to the substrate, which led to high corrosion rates under all conditions. Analysis of the corrosion products revealed that flow rate had no effect on the composition of the products, while the pr esence of sulfur significantly influenced the composition of the product film.

As offshore oil and gas exploration and development increasingly progress into deeper layers, the operational environment for well pipes becomes more challenging, with materials facing severe risks of corrosion failure under ultra-high temperature and pressure conditions. Objective: To elucidate the corrosion behavior and patterns of low-alloy steel well pipes under supersaturated supercritical CO 2 , this study focuses on P110SS. Through static weight loss corrosion tests, the influence of a wide temperature range (40° C~250°C) and ult ra-high pressure (1 MPa~70 MPa) on the corrosion rate of the material in a supercritical state was analyzed. SEM, EDS, and other analytical methods were employed to characterize the morphology and composition of the corrosion products. Results: Under simul ated marine conditions with a CO2 partial pressure of 10 MPa, the corrosion rate of P110SS peaked at 2.43 mm/a at 80° C and decreased continuously with increasing temperature, reaching 0.17 mm/a at 250° C. Below 7.35 MPa, the corrosion rate increased linearly with pressure. However, when CO 2 exited the dense phase, the influence of pressure on the corrosion rate became insignificant. Conclusion: Whether CO 2 is in a dense or supercritical state, the corrosion rate of P110SS initially increases and then decreases with rising temperature, without a change in corrosion mode. The corrosion rate was highest at 80° C, gradually decreasing and stabilizing above 180° C, with corrosion rate being controlled by the density of the corrosion products. As CO2 pressure increases, the corrosion rate rises, with P110SS being more sensitive to CO 2 pressure in the dense phase. This trend is related to the solubility of CO2 in water. This study provides valuable insights into the corrosion behavior and mechanisms of materials under supercritical CO2 conditions.

Protecting pipelines and flange connections from corrosion while ensuring they are leak-free, safe, and compliant with industry standards and regulations has become increasingly challenging. Pipeline corrosion professionals must now navigate various challenges that were once minor inconveniences but have now become everyday concerns. These challenges include an increase in chemicals in pipelines, the use of steam, increased pressures and temperatur es, fire safety, sour gas, and emissions. When these challenges come to the forefront, they can directly impact performance of the system and will increase downtime for operators. In this paper we will explore the resultant effects these challenges have o n corrosion prevention, particularly the effects on Electrical Isolation Kits and offer solutions to minimize downtime, streamline process and improve productivity. We will be addressing harsher media conditions such as sour gas, steam, CO2, CO, ammonia, and H2S. The results of these conditions include electrical bridging, permeation, material degradation, and higher corrosion levels. As the world embraces newer energy methods such as CCUS and Hydrogen all of which provide unique challenges that we will ex plore. With these newer methods comes a greater focus on greenhouse gases (GHG) reductions and has led to an increase in regulation and emission focus. In the paper we navigate through all the challenges facing flange corrosion prevention in 2024 and beyond.

For the development of deep -water oil and gas fields, the harsh conditions of the deep -water environment put forward higher requirements for co rrosion protection design. Through typical cases of deep -water corrosion failure of South China Sea subsea production system, this article analyzes the shortcomings of the current anti-corrosion standard for deep-water environment anti-corrosion design, and introduces the exploration and practice of the research on the materials and corrosion technology of oil and gas field development in deep -water environment. The core technology and experience obtained in deep water cathodic protection system, deep water underwater coating system, deep water material selection and risk assessment (especially HISC) are fully demonstrated, providing technical guidance for domestic deep water anti-corrosion design.

Carbon Capture and Storage (CCS) technology plays a pivotal role in mitigating climate change by reducing CO 2 emissions. The process, however, is complicated by phase changes in CO 2 due to temperature and pressure variations, and the presence of impurities such as water, H2S, SOx, and NOx, which can decrease water solubility and lead to water dropout at lower pH levels, thereby increasing corrosivity [1]. Additionally, impurities like oxygen may initiate further cathodic reduction processes that increase the risk of localized corrosion [2]. Traditional methods for predicting and studying corrosion have been an area of focus, however, they often fall short in addressing the complex, multifaceted nature of corros ion processes under varying environmental conditions. The objective of this research is to delineate the impact of impurities on the corrosion rates and mechanisms in different materials, including low-alloy steels, 13% Cr steels, and high -alloy grade mate rials. These materials were subjected to supercritical impure CO2 stream as well as electrochemical exposure in a brine solution continuously infused with CO2 along with impurities. Corrosion rates were determined through electrochemical methods such as polarization resistance and electrochemical impedance, alongside weight loss measurements. Surface analyses of corroded samples were performed using scanning electron microscopy and X -ray diffraction. The extensive data collected were utilized to develop empirical predictive models that estimate the influence of critical variables on corrosion rates and predict corrosion rate.

The repurposing of non-productive oil wells for CO2 storage offers a viable solution for reducing greenhouse gas emissions and combating climate change. Due to applied pressure and stresses, micro -annuli—small gaps between the cement sheath and casing is formed, that can act as ch annels for corrosive agents to interact with both cement as well as metal and the ions released could promote material degradation [1]. Furthermore, corrosion of cement -metal interface can also occur after the abandonment process (injecting a specialized cement slurry to seal the wellbore) could hamper the integrity of safe storage and allow leakage into surrounding formations [2]. This poses significant risks to the long -term durability and safety of the stora ge sites. This study aims to thoroughly investigate the chemical interactions and corrosion mechanisms at the cement -metal interface under diverse CO 2 conditions (Dense phase CO2 and CO2 saturated brine), utilizing a broad spectrum of electrochemical and analytical techniques. Methods such as optical microscopy, scanning electron microscopy, Fourier -transform infrared spectroscopy, transmission electron microscopy, and X-ray tomography are employed to examine the formation of reaction products and detect an y phase debonding at the interface. Additionally, Inductively Coupled Plasma - Optical Emission Spectroscopy analysis and Thermogravimetric analysis are employed to assess dissolution and carbonation levels, respectively.

This work is part of a research program investigating preferential weld corrosion in welded joints. The purpose of this study is to present the contributions of an extensive literature review and the main results obtained for 79 girth welds tested. The literature review revealed that preferential corrosion of welded joints depends on, among other things, the media and exposure conditions, the composition of the base metal and filler metal, and the welding process. Of these, the medium and exposure conditions play an essential role: to apply any criteria for the appropriate selection of the base metal and filler metal, it is crucial to know the characteristics of the medium and exposure conditions. The best -known criteria cited by the literature for predicting the galvanic behavior of a welded joint were based on tests conducted in high -conductivity media and non-conducive to forming a protective layer of carbonates. For the low conductivity media, which is the focus of this work, no consolidated criteria for mitigating preferential corrosion of welds were found in the literature consulted. The tests and analyses carried out in this project have verified that, in low conductivity media, preferential corrosion resulting from the formation of a galvanic pair is limited to a range of 200 μ m in the vicinity of the fusion line. The delta criterium, accepted in the literature for high conductivity media, is capable of reliably predicting only the cathodic character of the MS of a welded joint in low condutictivity media.

Pipeline In-line inspection (ILI) is a reliable and well -established technique to assess the integrity of pipelines. ILI requires an initial assessment of the pipeline condition and internal minimum passage before any ILI tool can be launched in a pipeline to ensure that the pipeline passage is suitable for the ILI. However, there are several factors and challenges that can prevent ILI in piggable and difficult to pi g pipelines, such as low flow, multi-diameter pipelines, tight bends, and pipelines with unknown restriction. This paper will go through a field experience, technical evaluation, and a success story of utilizing a Foam-based Eddy Current (EC) ILI tool to inspect a piggable pipeline where the ILI was not possible by conventional tools due to a major and unknown restriction in the internals of the pipeline. The tool successful deployment will allow for an accurate and reliable inspection and assessment of hig h restriction pipelines safely while eliminating the risk of stuck ILI tools. This opens a new window and opportunity for the revalidation and inspection of high restriction pipelines to maintain their integrity, reduce down time, and failures.

Universidade Federal do Ceará With the technological advances in offshore oil and gas exploration and production, the structures known as flexible risers have come to the fore because they enable deepwater activities. Despite their hig h corrosion resistance properties, risers can suffer deterioration, leading to failure accidents, high repair costs, and the risk of environmental and employee safety problems. Given the above, this work aimed to assess the corrosion resistance of steel with a eutectoid composition containing 0.49% Mn using the techniques of open circuit potential (OCP) monitoring over time, potentiodynamic polarisation (PP), and electrochemical impedance spectroscopy (EIE) in a medium of 3.5% (w/v) NaCl in the absence of and saturated with CO2. The surface morphology was investigated by optical microscopy. The experimental results showed that the corrosion current densities of the steel exposed to the environment with and without CO 2 are significantly similar. Finally, the EIE results showed that the polarisation resistance (Rp) is higher in the absence of CO 2, indicating the damaging factor caused by the presence of CO2.

The corrosion of steel poses significant economic and safety concerns, necessitating accurate predictive models to mitigate potential risks. This study presents a comprehensive investigation into the prediction of corrosion rates across diverse environmental conditions through the application of Adaptive Network -based Fuzzy Inference Systems (ANFIS). The experimental protocol encompasses testing of 127 samples of three materials P110SS, L80, and 2205 Duplex steel, each subjected to varying conditions, inclu ding temperature, H2S partial pressure, CO2 partial pressure, salinity, and moisture content. The corrosion rate serves as the essential indicator in this research. The ANFIS model is intricately constructed with six neurons in the input layer representing temperature, H2S partial pressure, CO2 partial pressure, salinity, moisture content and material type, while the output layer consists of one neuron for the corrosion rate. Results demonstrate the efficacy of the 6× 18× 1 ANFIS model in dynamically predicting the corrosion rate of the three materials used. A comparative analysis with Response Surface Methodology (RSM) underscores the superior predictive performance of the ANFIS model, as evidenced by lower Absolute Maximum Error (AME) and higher R2 values 0. 81. The developed model, alongside empirical correlations, presents a promising tool for corrosion engineers, facilitating efficient corrosion rate determination without the need for extensive AI model training.

The paper represents the green synthesis and inhibitive performance of pyrimidine derivative (PP) over Q235 steel in 15% HCl under dynamic conditions. The result of EIS suggests the rise in Rct with the rising amount of PP amount. PDP result reveals the mixed nature of PP inhibitive action. The PP performance value is 93% at 200 mg/L. Surface study reveals the development of protective film of PP over the metal surface. Density functional theory (DFT) suggests that the protonated form of PP shows stronger adsorption ability than neutral one. Molecular dynamic simulation (MD) confirmed that the adsorption geometry of PDH+ on iron surfaces exhibits more parallel orientation than PP.

Heat recovery steam generator (HRSG) units remove the heat from exhaust gases that come from gas turbines and utilized this heat to generate steam. Typical HRSG unit consist of economizer, evaporator and superheaters. This paper discusses a case study of corrosion fatigue as a damaged mechanism of evaporator tubes in a HRSG Unit. The tubes operating temperature is 507 ° F and operating pressure is 705 psig. The tubes were subjected to visual, chemical and metallographic analysis. Visual examination of the internal part of tubes showed cracks that perpendicular to the flow direction. Positive Material Identificat ion (PMI) was carried out on the tubes using X -ray fluorescence (XRF) and confirm the tubes chemistry is low alloy carbon steel. X -Ray diffraction (XRD) analysis was conducted for the deposits found inside HRSG evaporator tubes. The results indicated that the products are mostly Magnetite [Fe3O4] which support that the internal corrosion is due to oxygen attack. Moreover, the metallography micrographs suggest the type of damaged mechanism is corrosion fatigue. It was recommended to maintain optimum feed water chemistry (pH, dissolve oxygen, conductivity, TDS) into the steam generating system as per the water treatment program in order to control the internal corrosion, reduce the fluctuations in pressure and temperature during operation to minimize the impact of fatigue and to clean the ID side of the tubes from the accumulated corrosion deposits and scales.

随着海上油气勘探开发逐渐向深层发展,油井管服役环境俞趋严峻,材料在超高 温高压环境下面临严重的腐蚀失效风险。目的:为明晰在过饱和超临界 CO2 下低合金 钢油井管的腐蚀行为和规律,以 P110SS 为研究对象,通过静态腐蚀失重实验,分析 了宽域温度(40°C~250°C)和超高压力(4MPa~70MPa)对超临界状态下材料腐蚀速率规 律的影响。利用 SEM、EDS 等分析方法,对腐蚀产物的形态及成分等特征进行表征。 结果:P110SS 在模拟海洋工况 10MPa CO2 分压下,在 80°C下腐蚀速率最高,为 2.43mm/a,随温度升高腐蚀速率不断降低,250°C下腐蚀速率为 0.17mm/a。在压力 低于 7.35 MPa 时,随压力增加腐蚀速率呈线性增加。当 CO2 脱离密相态,压力对腐蚀 速率的影响不再显著。结论:无论 CO2 处于密相态或超临界态,温度对 P110SS 的腐 蚀速率影响规律均呈现先升高后降低的趋势,腐蚀模式未发生改变。腐蚀速率在 80°C 时最高,随温度升高逐渐降低,180°C以上基本保持平稳,腐蚀速率受腐蚀产物的致密 度控制。随 CO2 压力增加,腐蚀速率逐渐升高,P110SS 腐蚀速率对处于密相态下的 CO2 压力更为敏感,变化趋势与 CO2 在水中的溶解度有关。本研究为理解材料在超临 界 CO2 状态下的腐蚀行为和机理提供了有益补充。

Using the Mollier Diagram to analyze the environment of c oastal cities Shantou, Jiangmen, and Zhanjiang in Guangdong Province, indoor corrosion acceleration tests including wet heat tests, salt spray tests, and drying tests were designed for these locations based on the principle of energy equivalence. Four cycles of corrosion tests were conducted using Q235 carbon steel in the three corrosion acceleration tests designed above.The corrosion rate of Q235 carbon steel in the above three regions was studied using the weight loss method, and the surface corrosion mic rostructure of Q235 carbon steel was observed using SEM. Using Keyence's 3D confocal imaging to record changes in corrosion pits on metal surfaces. The results showed that with the extension of experimental time, the corrosion weight loss of Q235 carbon st eel followed the power function corrosion characteristics, and the corrosion rate of Q235 carbon steel was in the order of Zhanjiang>Shantou>Jiangmen in the above three regions. In the accelerated corrosion test of simulated marine atmospheric environment, Q235B carbon steel is mainly subjected to uniform corrosion, and the microstructure shows two stages of corrosion pit formation and corrosion pit smoothing. With the extension of the test period, the two stages alternate.

The effect of Ca-Mg microalloying on corrosion behavior of Al deoxidized low alloy steel in the simulated tropical marine atmospheric environments was investigated. The addition improves microstructural characteristics, increasing the corrosion potential by 70±10 mV and decreasing the corrosion rate from 1.66 mm/y to 1.57 mm/y over time. Furthermore, the addition of Ca -Mg has been observed to modify the morphological attributes, population density, dimensional parameters, and electrochemical properties of the prevalent inclusions. This modification is instrumental in shifting the underlying mechanisms that contribute to localized corrosion, which is often precipitated by these inclusions in the steel matrix.

Due to superior mechanical and corrosion resistance properties, high - strength aluminum alloys have been widely used in the aerospace field. Atmospheric corrosion and mechanical properties degradation of 2524 -T3 high-strength aluminum alloy are affected by environmental factors. A close relationship exists between corrosion factors and mechanical properties degradation of the alloy in different atmospheric environment s, which is meaningful to predict the service life. In the present work, atmospheric corrosion and mechanical property degradation of 2524-T3 high-strength aluminum alloy in different marine atmospheric environments are investigated. The corrosion evolutio n and surface topographies are analyzed. The relationship between the localized corrosion parameters and mechanical property degradation sensitivity is discussed. The corrosion of 2524 -T3 high-strength aluminum alloy exposed in the tropical marine atmosphe re is the most severe, attributed to the high temperature, high humidity, long TOW, and high Cl - deposition rates. Corrosion of the groundward surface is much more severe than that on the skyward surface because of the longer presence time of the electrolyte layer on the former. The EIS results are closely related to the corrosion evolution process. The severe atmospheric corrosion leads to degradation of mechanical properties. However, the degradation sensitivity does not increase with the exposure time, which has a great relationship with surface corrosion defects. The degradation sensitivity indexed by elasticity modulus is correlated with Dmax. The degradation rates indexed by elongation, reduction -in-area, and tensile strength show a close relationship with D'ave. (Fig. 1) Fig. 1 The Dmax versus the degradation sensitivity indexed by elasticity modulus (IE) (a), and the D’ave versus the degradation sensitivity indexed by tensile strength, elongation and reduction-in-area (Iσ-T, Iδ, Iφ,) (b). First Author Profile:Huiyun Tian. Her research interests are marine environment sensitive fracture behavior and mechanism. tianhuiyun@ouc.edu.cn。 Corresponding Author Profile:Zhongyu Cui. His research interests are marine environmental corrosion and protection. cuizhongyu@ouc.edu.cn。 School of Materials Science and Engineering, Ocean University of China, Qingdao 266100, China

The corrosion mechanism of a high corrosion resistance Zn -Al-Mg coating submitted to typical extremely harsh environments Wanning and Mohe was investigated. The findings revealed distinct corrosion rate patterns in each location. In Wanning, the corrosion rate initially increased and then decreased, whereas in Mohe, it exhibited the opposite trend. In the marine atmosphere of Wanning with high temperature and high humidity, corrosion preferentially occurs in the eutectic phase and extends to the inner of the coating along the eutectic phase near zinc-rich phase. Oxygen is uniformly distributed, sulfur is located in the upper layer, an d chlorine exhibits strong longitudinal migration ability and accumulates within the coating. The corrosion rate on the skyward side was smaller than that on the field -ward side in Wanning, and this difference between two sides decreased initially and later increased. However, in the urban atmosphere of Mohe with extremely low temperature, the local corrosion phenomenon is more obvious. Corrosion pit tends to form in the eutectic phase near the zinc-rich phase, exhibiting a broader upper part and a narrower lower part. The shape of corrosion pit gradually transitions from sharp to shallow. After 6 and 12 months of exposure, the corrosion rate on the skyward side was smaller than that on the field-ward side, and after 24 months of exposure, both sides exhibit ed similar corrosion rates.

Corrosion products provide key information fo r understanding corrosion mechanism. To date, element distribution in weathering steel (WS) rust layer (RL) at the nanoscale remains inadequately investigated. It is generally believed that the enhanced corrosion resistance of WS is due to the nanoscale gr ains tightly packed in the inner RL. However, there is a lack of investigation to address the elements distribution in the inner RL at nanoscale. In recent years, some researchers have proposed that the significant corrosion resistance of WS in SO 2-polluted industrial atmosphere can be attributed to the formation of non-cracked, uniform, and protective amorphous hydroxylated iron oxide. Dillmann [1] and Morcillo [2] pointed out that an unsolved issue regarding atmospheric corrosion of WS is related to the a morphous substances. This may be because the detection and study of amorphous substances are extremely challenging. This study investigates the microstructural and compositional evolution of corrosion products formed on WS under exposure to SO 2- rich atmosphere. Notably, the extremely unique RL feature on the WS after 12 months of exposure in SO2-rich industrial atmosphere was found, consisting of an outer RL, an inner RL with ultrafine grains, and a transition layer with amorphous. The Atom probe tomography (APT) analysis revealed, for the first time at the atomic scale, that the amorphous transition layer enriched with Ni, while the ultrafine grains in the inner RL layer contained Cr -rich and Si -rich particles. The interaction between the SO 2-rich atmosphere and the alloying elements in the steel plays a significant role in the formation and stability of the corrosion layers. The results provide insights into the corrosion mechanisms of WS in harsh industrial environments, contributing to the development of more durable and corrosion-resistant materials.

This study analyzes the corrosion behavior of five copper alloys exposed to outdoor environments at six locations, which employed CIE -Lab colorimetry and UV - VIS absorption spectroscopy to assess the extent of discoloration and the rate of corrosion. The results revealed that among the silver -like copper alloys, zinc white copper exhibited a significantly slower darkening rate compared to nickel white copper, highlighting its superior resistance to atmospheric tarnishing. For gold -like copper alloys, the darkening rates generally followed the order: aluminum bronze < nickel brass < tin brass. However, under the unique environmental conditions of Dunhuang, aluminum bronze demonstrated a markedly higher darkening rate. Additionally, to elucidate the mechanisms behind these observations, the study incorporated scanning electron microscopy (SEM), scanni ng Kelvin probe (SKP) analysis, and density functional theory (DFT) calculations. These methods provided insights into the morphology and distribution of corrosion products, highlighting differences in corrosion resistance. The work function of corrosion products and material migration capabilities were found to be critical factors influencing corrosion resistance. The findings provide valuable guidance for the development of more corrosion -resistant copper -based materials, with implications for their use in diverse atmospheric environments.

Atmospheric chloride deposition is a critical factor influencing metal atmospheric corrosion, and accurately estimating its spatial distribution is of great importance. Existing models for estimating atmospheric deposition rate often oversimplify the physical processes, leading to lower generalization performance and prediction accuracy. We compiled 544 records of atmospheric chloride deposition rates from six countries, including China and Australia. By analyzing the holistic physical process of at mospheric chloride deposition, 11 key environmental factors were identified. Based on the analysis, a genetic algorithm -optimized quantile regression forest (GA-QRF) method was proposed to quantitatively model the holisitc deposition process. The proposed model demonstrated superior predictive performance on the dataset, achieving a determination coefficient ( R2 ) of 0.935. Additionally, the model quantified the uncertainty of the predictions, achieving a 98.2% interval coverage rate at a 95% confidence leve l. To verify the generalization performance, three model interpretability methods were employed to ensure consistency between the black -box model and domain knowledge. Finally, using the proposed model, we constructed the first continental -scale dataset of atmospheric chloride deposition rates across mainland China which includes uncertainty quantification. This dataset can serve as a preliminary input for scholars in China for atmospheric corrosion prediction, maintenance protection, and material selection for equipment.

Surface hydrogenation, oxidation, and other corrosion -related reactions of uranium have attracted continuous concern for many years, because these processes are not only of great scientific interest, but also of significant practical importance for nuclear industries. Through several theoretical studies, we reveal that the 6d electronic states play important roles on the chemical properties of uraniu m. Our research progress can be summarized as follows: i) On γ -U surface, H 2 molecules dissociate barrierlessly due to s-d electronic hybridizations; ii) On α-U surface, there are also “s-d interaction” adsorption channels along which H 2 molecules dissociate barrierlessly; iii) Interactions between the three frontier molecular orbitals with surface d states lead to that H 2O dissociate spontaneously on the γ -U surface; iv) U -6d state is the only evolving state in different UnOm clusters, which hybridizes wit h U-5f states in U -rich clusters, and hybridizes with O-2p states in O-rich clusters.

A hot-rolled Cu-P weathering steel (WS) with a new microstructure was subjected to different cooling speeds for heat treatment, resulting in three microstructures: ferrite (F), ferrite+granular bainite (F+GB), and lath bainite (LB). The corrosion resistance of these microstructures under simulated industrial atmospheric corrosion conditions was evaluated by a cyclic immersion accelerated corrosion test. All the microstructures showed two stages in their mass loss curves, with a slow decrease in corrosion rate in the early stage of the cyclic immersion (0-48 h), during which the formed rust layer had limited inhibition on corrosion.Subsequently, the rapid decline in corrosion rate during the latter part of the cyclic immersion period (48-96 h) indicates that stable rust layers are beginning to form. During the entire cyclic immersion process, the average corrosion rate of the LB steel was slightly lower than that of the F+GB steel, but the corrosion kinetics of the two were similar. Compared with the F steel, the corrosion kinetics of the other two steels showed obvious differences. The average corrosion rate of the F steel was the smallest at the beginning and end of the cyclic immersion, but the difference was not significant. It was much lower than that of the other two steels at 48 h, indicating that the rust layer formed by the F steel in the early stage of cyclic immersion had certain protective properties, but the stability of the rust layer was poor in the latter stage. This was attributed to the change in the composition o f the corrosion products formed on the different microstructur e matrix. The proportion of α- FeOOH in the F steel was the highest at 24 h and 96 h of cyclic immersion, while that in the LB steel and the F+GB steel was lower. At the same time, the surface roughness of the F steel after descaling was the smallest, while that of the LB steel and the F+GB steel was larger. The high α -FeOOH content in the F steel inhibited pitting corrosion and improved the uniformity of corrosion. However, the lower corrosion po tential and increased corrosion heterogeneity in the LB steel and the F+GB steel were attributed to the higher proportion of small-angle grain boundaries and higher dislocation density in the microstructure.

Copper conductor, due to its low resistivity, ductility and other advantages, is often used in aircraft lightning protection lap wire [1]. Aircraft lightning protection lap wire is a stable low impedance electrical path which is an important guarantee of aviation equipment to resist lightning. With the increase of the service time of the airplane, corrosion will lead to the increase of its resistance, and then affect its ability to resist lightning, which will cause great threat t o the flight safety of the airplane [2]. Therefore, it is necessary to predict the corrosion damage process of the lightning protection lap wire and its effect on the resistance. In this paper, the corrosion model of the lightning protection lap wire is est ablished based on the cellular automata algorithm. According to the corrosion process of metal dissolution, corrosion product generation, acidic hydrolysis, etc, copper, cuprous ions and other cells are set up to simulate the damage evolution process and t he trend of corrosion weight loss. Then the discrete points are transformed into a grid, and then into a solid, retaining the complex irregularity of the etch pit morphology. The corrosion pit morphology is imported into COMSOL to simulate the trend of res istance. The damage evolution process under real conditions is simulated by immersion corrosion experiments that verify the accuracy of the simulation. The results show that in the corrosion process of the aircraft lightning protection lap wire, the corrosion weight loss grows faster in the early stage and slows down gradually in the late stage, and its resistance also grows faster in the early stage and slows down gradually in the late stage. Therefore, the research in this paper is of great significance f or predicting the corrosion damage of aircraft lightning protection lap wires and the resulting changes in the resistance value.

The commercialization of Ni -based catalysts in CO 2 dry reforming of methane (DRM) suffers from their quick deactivation. Here, we reveal each reaction pathway for DRM based on the Ni catalyst composition and geometry under working conditions, through one working platform combining in situ high resolution Cs corrected environmental transmission electron microscopy and electron energy -loss spectroscopy coupled with mass spectroscopy. The formation of Ni3C has been found to inhibit the decomposition of CO 2 and CH4, and to promote the formation of onion - like carbon to encapsulate the Ni catalysts, leading to the deactivation of the Ni-based catalysts. Designing the suitable supports or promoters to keep the Ni surface structure under Ni -NiO cycle can drive the simultaneously amorphous carbon deposition - consumption cycle and minimise the coke formation. This research is not only for developing coke resistan ce Ni catalysts in the DRM, but also significant for investigating many catalysis challenges both in research and engineering.

Ni is considered to be an effective element to enhance the corrosion resistance of steel [1]. But high levels of Ni increase the cost of the material. Possible ways to reduce the cost are to reduce the Ni content as well as to add other alloying elements to improve the corrosion resistance by reducing the content or by synergizing the effect. This paper aims to use wet dry cycle tests to study the synergistic effect of a small amount of Ni and Cr elements on the corrosion mechanism of pearlite steels and the evolution of the rust layer during this process. It is expected that the alloying design of a small amount of Ni and Cr will become an effective method to improve the corrosion resistance of pearlite steels. The results of the study show that 0.2Ni steel has superior corrosion resistance. After adding a small amount of Ni, the content of Cr2O3 increases, and there is a synergistic effect between a small amount of Ni and Cr elements, which accelerates and promotes the transformation of corrosion produ cts, and the NiFe2O4 generated during the corrosion process is electronegative, attracting the agglomeration of cations, promoting the refinement and aggregation of rust layer particles, and enhancing the densification of the rust layer. In addition, the interlamellar spacing of 0.2Ni steel is refined, and the residual cementite at the interface of the rust layer matrix effectively improves the local corrosion resistance.

In the actual atmospheric environment, the liquid film on the metal surface has been constantly evaporating and condensing as the climate and meteo rological conditions change, showing the characteristics of dynamic liquid film, so the dynamic liquid film corrosion is closer to the atmospheric environment. A concentric three - electrode array local electrochemical test method was used to study the effec ts of parameters such as dynamic liquid film change rate, initial liquid film thickness, and number of liquid film change cycles on the electrochemical behavior of pure iron corrosion. The electrochemical response of the dynamic liquid film change rate, th e initial liquid film thickness, and the number of cycles to the pure iron interface is studied. Results show that with the gradual increase of the dynamic liquid film change rate, the corrosion process of the electrode varies with the external environment. As well as the unbalanced response speed between the electrodes inside the electrode, the local cathode and anode differentiation of the corroded electrode is serious, and the local corrosion tendency increases; when the initial liquid film thickness is thin, the corrosion potential and coupling current are unevenly distributed, and the cathode and anode differentiation is serious. The corrosion rate is large; with the increase of the number of dynamic liquid film cycles, the position of the cathode and a node is fixed, and the local corrosion tendency of the initial state, half cycle and final state first increases slightly, and then the volatility gradually decreases. In the evaporation process of the thin NaCl liquid film on the surface of the pure iron electrode, as the liquid film continues to thin, its corrosion tendency first increases, then decreases, and then increases; the liquid film changes from a uniform liquid film to discontinuous and dispersed Liquid film: In the middle and late stages of liq uid film thinning, due to the influence of corrosion products and crystalline salts, the diffusion path of oxygen changes, resulting in the edge position being controlled by oxygen diffusion resistance.

The influence of nitrate ions on the corrosion of Q 420 steel in chloride environment was studied by electrochemical means. The results show that in solutions where the ratio of nitrate ions to chloride ions is greater than 0.09%, nitrate ions have an inhibitory effect on the corrosion of Q420 steel in chlo ride environment. However, no inhibitory effect was observed in solutions where the ratio of nitrate ions to chloride ions is less than 0.09%. Furthermore, nitrate ions are unable to inhibit pitting corrosion of Q420 steel in chloride environment.

The data mining methods were achieved for the evaluation and prediction of the corrosion degre e. Firstly, the environment parameters that highly correlated with corrosion rate were selected by Pearson Correlation Calculation. Then the machine learning methods such as Artificial Neural Networks were applied to build mapping models between environment and corrosion rate which were obtained from long-term atmosphere exposure testing. The high prediction accuracy and generalization ability of the well-trained ANN model were verified by predicting the corrosion in new locations. Furthermore, a high-resolution map for materials degradation was drawn based on the predicted data from hundreds of cites in China. We also carried the data mining methods on different materials including the plastic, rubber, mental, and polymer coating. Furthermore, we obtained t he aging/corrosion distribution map in worldwide and local areas. The model s developed in this study would benefit to the targeted materials selection and differentiated protection.

This paper mainly studies the corrosion problem of weathering steel materials used in railway freight car bodies. Using optical microscopy, scanning electron microscopy (SEM), energy spectrum and X -ray diffraction, among other techniques, the corrosion characteristics of weathering steel materials used in railway freight car bodies are analyzed. At the same time, ion chromatography technology is used to study the residual liquids and foam solutions within the car body. The results show that both the residual liquids and the foam solutions contain high concentrations of Cl-and SO42-, which are the main factors causing corrosion of the railway freight car body. Additionally, the door frame area of the car body is subject to prolonged moisture, which accelerates the electrochemical corrosion of the weathering steel material used in the door frame, resulting in more severe corrosion of the door frame compared to other parts of the car body.

To clarify the types and distri bution of soluble salts in marine effluent ceramics, two kinds of artifact samples with different porosities, white porcelain and colored pottery, from “Nanhai I” shipwreck were tested by IC and SEM -EDS. The results showed that soluble salts primarily comp rising NaCl and Na 2SO4 are predominantly found within the pores and at the interface between the carcass and glaze, and the salt content is higher in colored ceramics with larger porosity. To improve the desalination efficiency, a non -destructive vacuum de salination device suitable for a wide range of artefacts and capable of dynamic monitoring was designed. Firstly, the effect of vacuum degree on desalination efficiency was investigated by using low-temperature glazed porcelain simulation samples. The resu lts showed that within the range of -100 kPa to atmospheric pressure, the larger the vacuum degree, the higher the desalination efficiency, which was 1.8 times higher than that of atmospheric pressure immersion. Concurrently, both white porcelain and color ed pottery cultural relics samples were used to comparative desalination experiments under vacuum and flowing water conditions. The results indicated that colored pottery, with its higher porosity, exhibited a faster desalination rate. In 120 h with flowing water, colored pottery removed a total of 11.540 mg of Cl-, whereas white porcelain removed 4.490 mg, representing a desalination rate 2.6 times that of the former. Under vacuum conditions, colored pottery removed 39.970 mg of Cl - in 120 h, which is 3.5 times the rate of desalination achieved with flowing water.

This research was prompted by the discovery of unusual corrosion in a series of archaeological gold masks crafted from 50 – 100 μm thick gold foil and unearthed from the Sanxingdui archaeological site in Sichuan, China. Despite the prevailing assumption that gold artifacts are corrosion-resistant and malleable, some of the gold masks unearthed in 2023 exhibited brittle and fragile characteristics. Morphological studies employing metallographic microscopy and scanning electron microscopy with energy-dispersive spectroscopy (SEM -EDS) revealed the presence of intergranular cracks and attributed the embrittlement to preferential corrosion of intergranular Pb - containing phases. Simulated samples of the Au -Ag-Pb alloy with compositions and microstructures similar to those of the ancient artifacts were created, exhibiting three main microscopic constituents: The Au -Ag continuous phase, the Au 2Pb phase, and the AuPb2 phase intermingled with reticular Pb oxides. Scanning electrochemical cell microscopy (SECCM ) technology was employed to conduct a quantitative analysis of simulated Au -Ag-Pb alloy samples to compare the electrochemical properties of the different phases at the microscopic level. Tafel analyses were performed for each testing spots. The results revealed an electrochemical activity order of AuPb 2+PbxOy >> Au2Pb > Au -Ag, which elucidated the varying levels of retention observed for different components in gold masks. The AuPb2+PbxOy phase was the phase with the highest corrosion priority. Despite t he relatively low electrochemical activity observed in the Au2Pb phase, it demonstrated a notable advantage in activity compared to the Au -Ag phase. This finding aligns with the long-term corrosion observations observed in the gold mask samples. The study provides a reference for subsequent protection strategies and shows the importance of corrosion inhibition in Pb -containing phases. It also demonstrates the potential of SECCM in analyzing and conserving metal artifacts.

The studies conducted at the Shanghai Museum demonstrated the promising application of the pulsed Nd:YAG 1064nm laser for the challenging bronze cleaning tasks that are difficult to address with conventional methods. Specifically, this laser is effective for: 1) removing thin corrosion from substrates prone to abrasion, such as Chinese mirrors with particular patina and gilt bronze; 2) removing pitting corrosion without causing further surface loss; 3) addressing complex degradation products resulting from past intervention, which are usually insoluble in non-aggressive solvents; and 4) cl eaning surface with complicated morphology, such as the typical delicate reliefs on Chinese bronzes [1]. This work reports successful application examples on various bronze objects and optimization methods, including the adjustment of working parameters, the use of gel mediums during cleaning, the combination of laser with other cleaning techniques, and the flexible manipulation of the laser handpiece [2-3]. Mechanistic studies were conducted on expendable bronze fragments and mock -up samples to investigate the laser-material interaction. Preliminary findings indicate that, in addition to composition, the consistency of corrosion significantly influences the process. The spallation mechanism, distinct from the selective vaporization commonly dominating the stone material cleaning, requires careful consideration for operational safety while suggesting broader application potential.

Bronze artworks, noted for their exceptional craftsmanship, possess substantial historical, artistic, scientific, and socio-cultural worth. Nevertheless, these artifacts are susceptible to erosive factors such as environmental acidic constituents, air pollutants, and microbial activities, all of which lead to their deterioration and corrosion. Since the late 19th century, research on the corrosion mechanisms of bronze has mainly concen trated on chemical and electrochemical processes. Although the influence of microorganisms has been recognized, it has not gained adequate attention in the conservation of metal artworks. Microorganisms, being the key participants in the elemental cycling of the planet, can notably contribute to corrosion. Their involvement modifies the electrochemical behavior at the interface between the metal and the corrosive medium. Hence, studying the interactions between microorganisms and metals is of crucial import ance, as it not only provides a comprehensive comprehension of the corrosion process but also offers potential for developing green and sustainable conservation approaches. This paper aims to summarize the progress made both domestically and internationally in understanding microbial influences on bronze corrosion and prevention. The objective is to advance scientific and technological methods for the preservation of cultural relics in China.

The Pujindu Site in Yongji, Shanxi Province,China, is a notable ancient ferry location on the Yellow River. During the Tang Dynasty(724 AD), iron objects, such as cattle and human figures, were cast as ground anchors for the Pujindu Bridge. These iron objects, excavated in the 20th century, re present a significant collection. Rescue protection was performed in 2004. Nowadays, these iron objects are experiencing new forms of corrosion, including extensive layered spalling, which poses a threat to the matrix. In this study, representative cross -sectional samples of layered spalling were collected and analyzed using microscopic morphology, X-ray diffraction, and Raman spectroscopy.The results show that the corrosion phenomena primarily consist of black-brown corrosion layers (BBL) parallel to the outer surface, along with red-brown corrosion layers (RBL) and cracks. The BBL primarily cover the cracks and the outer surface. The corrosion products include goethite (α-FeOOH), lepidocrocite (γ-FeOOH), akaganeite (β-FeOOH), magnetite (Fe 3O4), and hemati te (Fe 2O3). The lepidocrocite content is higher in the RBL compared to the BBL. Cracks within the corrosion layer (CL) are filled with needle -like crystals and exhibit high chlorine (Cl) content. High humidity and rainfall facilitate the entry of water and oxygen into the objects through these cracks, leading to the formation of corrosive galvanic cells on the iron surface. Iron initially oxidizes to form lepidocrocite, which gradually transforms into goethite and akaganeite under environmental influences. Additionally, iron may participate in oxidation reactions to produce magnetite, which can further oxidize to form maghemite and hematite. Fluctuations in atmospheric temperature and humidity cause the surfaces of artifacts to undergo repeated drying and wetting cycles. This process leads to the development of corrosion cracks and the continuous formation of new iron oxides within these cracks. The varying internal stresses among different corrosion products contribute to the creation of additional cracks. Over time, the prolonged environmental effects result in ongoing deterioration of the objects until they are completely damaged. Understanding these processes is crucial for developing effective protection strategies for iron artifacts.

To address the issue of corrosion in iron relics, a six -group fluorocarbon protective coating was developed. This was achieved by synthesizing silica-composite graphene powder through hydrolysis, using fluorocarbon resin as the film-forming resin. Furthermore, we compounded Schiff's base with other potent corrosion inhibitor and fertan corrosion inhibitor to enhance the coating's protective capabilities. The prepared samples were characterized using scanning electron microscopy (SEM), infrared spectroscopy (FT -IR), and X -ray diffraction (XRD). Additionally, the coating was investigated by electrochemical alternating impedance spectroscopy (EIS). The findings indicate that the coating with Schiff base compounde d with the corrosion inhibitor and G/SiO 2 as the filler demonstrates superior overall performance. Specifically, it exhibits grade one adhesion, an average film thickness exceeding 100 μm at a single application. The EIS results impressively demonstrated that the coating exhibited an impedance modulus of 6.51x10 11 Ω·cm2 at 0.01 Hz, following 7 d immersion period in a 3.5 wt% NaCl aqueous solution. This remarkable performance signifies the coating's exceptional resistance to electrochemical corrosion.

Ceramics excavated from the ground or out of the water are often covered with a layer of sediment, affecting the object's aesthetics and impacting its subsequent preservation. In this paper, taking 24 pieces of celadon ceramics from the Na nhai I shipwreck as an example, using super -depth-field microscope, X -ray diffractometer (XRD), scanning electron microscope -energy spectroscopy (SEM -EDS), Raman spectrometry, etc., to study the types of deposits, deposition morphology and process, and the effect of deposits on glaze corrosion, and obtained the following results: 1 The white sediments on the glazed surface were mainly aragonite, gypsum and clay particles. The transparent sediments are primarily composed of spherical boehmite and magnesium silicate as aggregates of curved flakes. The yellow sediments mainly comprise iron-rich magnesium silicate, acicular siderite and goethite, and iron-rich clay particles. The black sediments mostly contain iron-rich magnesium silicate and various iron-sulfur compounds. The reddish -brown sediments are mostly hydronium jarosite. 2 Fe and Mg silicate deposits are common and formed when the glaze material is hydrolyzed with environmental ions. Mg and Fe silicate formation is highly dependent on the pH of the solution, requiring pH > 8 for magnesium silicate precipitation and pH > 6 for iron silicate precipitation at room temperature. Fe silicates are deposited first in crevices, followed by Mg silicates; in pores and surfaces, Fe silicates and Mg silicates are deposited simultaneously. The pH change of the solution, the availability of Mg, Fe, and Si elements, and the solubility of the secondary phase precipitation together affect the deposition morphology of the glaze corrosion layer. 3 The Fe and Mg silicate deposit layer accelerates the glaze's corrosion, and the glaze's corrosion promotes the formation of the deposit layer. 4 Mg and Fe silicates are hygroscopic and can form an alkaline microenvironment locally after excavation, thus accelerating the corrosion of the glaze and further deposition of Mg and Fe silicates. Therefore, keeping the ceramics in deionized water is recommended after they are excavated out of the water. At the same time, desalination treatment is carried out to r emove the soluble salts, after which a weak acid solution is used to remove these two deposits chemically. The research results will provide supporting data for the subsequent scientific and adequate protection of this batch of precious ceramics.

To explore the potential protective effect of UV illumination on the tin bronzes, the corrosion behaviors of four ternary Cu -Sn-Pb alloys with varying tin contents in a chloride-containing borate buffer solution (pH 8.4) were investigated in both the dark and UV illuminated conditions. UV illumination was found to consistently inhibit bronze corrosion across varying tin contents by facilitating the formation of a compact SnO 2 layer on the surfaces. This process is referre d to as photo -induced passivation. Concerning the effect of Sn content on the photo -induced corrosion process, a substantial Sn enrichment within the patina layer favors the formation of this compact oxide film more readily. Moreover, the oxide films on high-tin bronzes generally exhibit greater photostability and provide more long -lasting protection compared with low -tin bronzes.Two kinds of artificial patinated bronzes were prepared to further access the inhibitive effect of photo -induced passivation trea tment on the bronzes covered with typical patina layers. The maximum inhibition efficiencies achieved were 93.1% for the patinated Cu5Sn bronze, which is covered with a Sn-rich single-layered patina mainly consisting of cuprite, and 82.4% for the patinated Cu10Sn bronze, which features a Cu2O/CuCl inner layer and a Cu2(OH)3Cl outer layer. These values are comparable to those achieved by organic substances used on various artificially patinated bronzes.Overall, photo -induced passivation treatment can effecti vely mitigate the corrosion of Cu -Sn-Pb alloys without introducing foreign substances that might interfere with the archaeological information of bronze artifacts during the preservation process. However, further research is still necessary before it can be applied to actual bronze artifacts.

Severe brittleness, curl and even fracture, and other self -destructive diseases on the gelatine paper-based photographs with important historical value seriously damaged the safety of these cultural relics. However, people lack attention to its microstructure, disease mechanisms, and restoration methods. This paper mainly includes the following three aspects. (1) Firstly, we study the current state of the Republican historical photographs with badly brittle, curled and broken characteristics in the Second Historical Archives of China. Subsequently, on the analysis basis of their material structures and compositions, simulated samples with different degrees of curl and shrinkage were prepared by regulating the humid -heat environment to study the influence of the humid-heat environment on the changes of regular curl and shrinkage, further to reveal the correlation between the microstructure of photographs and the curling changes. (2) A study on the mechanism of conformational changes in gelatine paper-based photographs under the dry -wet cycles. The gelatine film samples with different shrinkage rates were firstly prepared through alternating dry-wet cycles. Then, through the correlation between the molecular structure, crystallinity, functional group change and macroscopic properties of gelatine films with different shrinkage changes were explored, and the mechanism of the curling and brittle fracture caused by the change of gelatine properties under the dry-wet cycles was revealed. (3) Research on the restoration a nd conservation of brittle and curled historical photographs. On the basis of previous disease mechanism, an amphiphilic glycerol triglycidyl ether emulsion was developed to improve the flexibility of photographic based on gelatine, and the restoration process of dissolution and depolymerization, flattening and shaping was designed to eliminate the brittle and curling disease of gelatine paper-based photographs. This method has been successfully applied to the restoration and conservation of several histori cal photos in China, and good results have been achieved.

Metal chaplets were frequently used in ancient Chinese bronzes. The use of chaplets has been regarded as technological progress for a long time; nonetheless, the research shows that there is a transition zone of oxidation between chaplets and metal body formed during the solidification of bronzes, which negatively impacts these bronzes. To date, the transition zone has attracted insignificant r esearch attention. In this study, the scanning electron microscopy –energy-dispersive X-ray spectroscopy (SEM-EDS) analysis on elemental composition and metallographic investigation of the transition zone were carried out in a reconstructed bronze tripod. It was found that the transition zone mainly consisted of copper oxides. X -ray diffraction (XRD) analysis further reviewed that the basic composition of the zone was cuprous oxide, which was formed during the solidification process of the bronze vessel due to its high - temperature and low -oxygen environment. The existence of the transition zone possibly led to preferential corrosion during usage, and thus caused the shedding of chaplets and damage the integrity of bronzes. The existence of this inevitable transition zone indicates the occurrence of inherent defects in the metal chaplet technology. Although this technology can improve the casting success rate and is a progress in social production, it can also affect the integrity of bronze and is a compromise of the bronze casting technology itself.

Based on the passivation of iron in alkaline solutions, aqueous alkaline treatment has been taken as an eff ective desalination technique to increase the stability of archaeological iron. However, chlorides may destroy the passivation of iron artifacts, causing damage to the treated artifacts during desalination. In this study, electrochemical and microstructure analyses were used to evaluate the corrosion behavior of iron artifacts, and to quantify the impact of chloride ions present within both the rust layer and the alkaline solutions on iron corrosion. The study revealed that even with the presence of chlorid e within the rust layer, alkalinity ensures passivation, thereby limiting the corrosion rate of iron artifacts. However, the passivation weakens as the concentration of ‘free’ chloride ions in the alkaline solution increases due to their migration from the rust layer, leading to active corrosion. A chloride threshold value (CTV) of 355ppm in 0.1 mol/L NaOH solution was established as a chloride level for the replacement of the alkaline solution to ensure the safety of artifacts during desalination treatment. The determination of CTV during the desalination process is of practical importance, and can guide the timely replacement of the desalination solutions to prevent chloride-induced iron corrosion during desalination treatments.

In the outdoor environments, stone artworks suffer from severe degradation due to chemical, physical and biological phenomena triggered by acid rain, atmospheric pollutants/microbial spore depositions, etc. Liquid/gaseous water and soluble salts are the essential causes of stone weathering, and there is an urgent need to protect the surface layer of stone artworks against weathering. Recently, superhydrophobic materials with excellent hydrophobicity and self -cleaning properties show great potential as protective coatings, yet the poor consolidation effect and mechanical durability, insufficient antimicrobial property, as well as potential pollution/health risks upon fabrication impede their application. In this study, the coating sols were prepared via a one -pot fluorine -free method, by tuning the molar ratios between trimethoxyoctylsilane (TMOS), ZnO tetra pods (T -ZnO) and SiO 2 nanoparticles. To apply, superhydrophobic surfaces were obtained on substrates effortlessly by brushing/spraying and subsequent gelation of the sols. Exploiting the photocatalytic property and intrinsic bioactivity of T-ZnO, as-prepared coatings showed good biocidal effect. With a very low amount applied (10 g/m 2), the coating prepared with the ratio TMOS/SiO2/T-ZnO=3/1/1 demonstrated the highest hydrophobicity (166° ), as well as the best antimicrobial effects against both Gram -positive/negative bacteria (i.e., 82% and 78% respectively, with the concentration 2.0 mg/mL). Besides, the as -prepared coatings also exhibited high resistance to chemical erosion and mechanical abrasion (withstand 100-cycle tests), owing to the isotropic high me chanical/chemical strength of T-ZnO in the 3D. Moreover, by slightly increasing the coating amount to 30 g/m 2, the surface (0 -10 mm) mechanical strength of the substrate improved (~20%), as evidenced by micro-drilling resistance tests. The mechanical stren gth originated from the polycondensation of TMOS in the presence of T-ZnO, in which T-ZnO acted as the skeleton fillers inside the silica gel networks to further enhance its strength in the three dimensions. With the facile synthesis and desirable multi -functionalities, as-prepared coatings are promising for the sustained maintenance of outdoor built -heritage and stone artworks.

The long -term exposure of bronze artifacts to various corrosive environments can lead to the formation of corrosion products that may cause significant damage to the artifacts. Therefore, accurately identifying the composition of these corrosion products, particularly harmful chloride-containing compounds and their distribution on the surface of the bronze, is crucial for the restoration and preventive conservation of these artifacts. However, some harmful corrosion products, such as basic copper chloride and cuprous chloride, are often covered by other corrosion layers, making them difficult to detect using traditional sampling methods, which also involve a degree of uncertainty. Consequently, obtaining both the composition and distribution of corrosion products, especially hidden chloride -containing harmful rust, in a non - destructive manner can more effectively aid in the precise protection and restoration of bronze artifacts. In this study, Terahertz Time -Domain Spectroscopy (TDS) was applied for the in-situ analysis and imaging of corrosion products on bronze artifacts. A terahertz spectral database for standard corrosion products on bronze was established through THz -TDS measurements, including their extinction coefficients, refractive indices, and fingerprint spectra. Simulated corroded copper samples were prepared using hydrochloric acid solution, and the thickness and composition of the corrosion layers were determined using the time -of-flight delay of the terahertz signal and the terahertz database. This technique was also successfully applied to the in-situ, non-destructive analysis of corrosion products on bronze artifacts unearthed from the Sanxingdui site in Sichuan Province.

In 2016, a relatively complete rudder of an ancient sand ship came out of the water near Rongcheng, Shandong Province. On the basis of using wood technology, the rudder stock, tiller, lap head and rudder blade are organically connected as a whole through a vari ety of iron components such as iron pin (round and flat) and iron hoop. Through metallographic analysis, SEM EDS, X-ray diffraction, ion chromatography and other analysis, the metallographic structure of iron matrix of iron components such as iron pin and iron hoop was determined, and the stratification of corrosion section, elements and phase distribution of rust were analyzed. The results show that the flat iron and round iron are ferrite structure, which are typical wrought iron. The ferrule has at least two kinds of structures, ferrite and ferrite+pearlite. It can be judged that it contains wrought iron and hypoeutectoid steel, which have been forged. The structure and chlorine content of the rust layer of iron components are in line with the corrosion c haracteristics of iron relics in marine water. The rust of iron components generally consists of 2 -4 layers, the outermost layer is a calcium and siliceous condensate layer, the second layer is a mixed layer of condensate and yellow rust, the third layer is a dense rust layer alternating black and yellow, and the innermost layer is a yellow rust layer close to the substrate. The corrosion products of iron components are mainly iron hydroxide and oxide, including magnetite(Fe 3O4), goethite(α-FeOOH), lepidocrocite(γ-FeOOH) and akaganeite (β-FeOOH). It is worth noting that through the analysis of iron sulfide compounds, element S does not completely exist in the form of iron sulfide compounds, and the Raman spectrum surface scan results show that part of S exists in the form of elemental sulfur (S8). This study provides a scientific basis for the further protection and restoration of the rudder, and has an important reference value for the protection of wooden and iron cultural relics in marine water.

This Research aims to systematically elucidate the corrosion mechanisms and pathogenesis of ancient bronze materials. Building upon a comprehensive analysis of the corrosion characteristics observed in bronze archaeological samples from various regions, we conducted a series of simulated corrosion experiments under soil burial conditions to elucidate the corrosion characteristics and ra tes of bronze materials, as well as their quantitative relationships with environmental indicators. Additionally, we established a preliminary evaluation model for assessing the impacts of corrosion. The mixture of copper, tin, and lead powders was exposed to a gaseous environment, and the exposure results were characterized by mass spectrometry analysis. The results indicate that the oxidation rates of components within the copper-tin and copper -lead systems are maximized when the content of tin or lead re aches 15%; for the copper-tin-lead system, the peak oxidation rate is observed when both tin and lead contents are maintained at 20%. Furthermore, relative humidity levels at 40% and oxygen concentrations exceeding 11% emerged as critical thresholds influencing changes in oxidation rates. Through theoretical calculations, the impact of alloy element ratios on the corrosion behavior of low tin bronze material was elucidated, and the adsorption patterns of oxygen atoms on both the surface and subsurface layers of the alloy were characterized. Finally, we concentrated on the typical issue “bronze disease”, investigating the corrosion behavior of four distinct types of tin bronze alloys and ancient bronze coins under various conditions, including soil environmen ts, continuous immersion, and acidic or alkaline atmospheres. A model for segregation corrosion in low tin bronze associated with “bronze disease ” was subsequently developed.

Organic acids are common pollutants in the display and preservation environment of cultural relics, which can cause corrosion of artworks and affect the safety of artworks. Recently, blue crystalline substances were found on the surface of some enamel wares on display and white crystals were f ound on some bricks in storage in the museum. Therefore, in this study, organic acids in the preservation environment were determined by different methods, and the source of these compounds were identified. The air inside the showcase, wooden cabinet, and ambient with large spaces was sampled by the absorption solution of ultrapure water and analyzed by Ion Chromatography (IC). Gas detector tubes were also used to rapidly determine the acetic acid concentrations. Pollutants in packaging boxes with small spaces were enriched by solid -phase micro -extraction arrow and analyzed by Gas Chromatography-Mass Spectrometry (GC/MS). The results show that concentrations of acetic acid in showcases and cabinets are much higher than that in the ambient air. Meanwhile, acetic acid concentrations increase when putting exhibition appliances in showcases. The GC/MS analysis results show that several kinds of carboxylic acids are identified inside the packaging boxes, including acetic acid, pentanoic acid, and hexanoic acid, wh ich are not found in their preservation ambient air. These results indicate that the corrosion of enamel wares and bricks is mainly caused by the organic acids emitted from exhibition and preservation materials. Moreover, the results of gas detector tubes are consistent with that of IC, which means that gas detector tubes can be used to determine the concentration levels of acetic acid in some specific situations. This study clarifies the determination methods of organic acids in different preservation environments. The sources of pollutants are also identified, which provides a reference for the preventive conservation of cultural relics during exhibition and preservation.

A large number of bronze artifacts have been unearthed from the Sanxingdui site. Compared to the rich research on the types of artifacts and the sources of ores, there is relatively less summary of typical corrosion products and explanation of the corrosion mechanism. This study conducts a comprehensive analysis and detection of the corrosion products on bronze artifacts unearthed from the No. 3 and No. 4 sacrificial pits. It was found that there are various copper, tin, and lead corrosion products. These corrosion products almost do not contain the traditionally harmful rust containing chlorine, but some powdery corrosion products, such as non -crystal tin and lead corrosion products, have certain damage to the structure and strength of the artifacts and also have the characteristics of harmful corrosion. Moreover, further changes may occur with the dehydration of tin corrosion products, and conservation should be carried out in the subsequent process. Affected by the burial of ivory in the environment, there is a large amount of phosphate in the corrosion and most notably, a previously unreported lead-tin yellow corrosion product was found. Combined with environmental analysis, it is summarized that the main process that occurred during the burial of bronze artifacts unearthed from Sanxingdui is the oxygen -rich and water -retaining environment without chlorine corrosion, with the loss of copper and lead, and the tin corrosion products remain in the matrix, maintaining the original appearan ce of the artifacts, while forming a regular distribution of lead-rich and copper-rich layers on the surface.

In order to reveal the corrosion mechanism of the bronze tripod during Warring States Period excavated in Tianshui City, we used Cu -Sn bronze pieces to simulate the tripod sample, and prepared soil simulation solution according to the composition of buried soil to characterize the corrosion behavior of the bronze sample systematically. The surface morphology and chemical composition of the samples before and after corrosion were characterized by metallography microscope, roughness tester, contact angle measurement, SEM, EDS, XRD, XPS methods, and the OCP, EIS and Tafel tests of Cu -Sn bronze samples under different corrosion periods was carried out by electrochemical workstation. The results show that the main components of the passivated film are CuO and Cu 2(OH)2CO3, and the harmful corrosion is Cu2(OH)3Cl. The contact angle of the bronze sample decreases gradually and the roughness increases gradually over time, which is mainly caused by the corrosion products generated on the sample surf ace. Moreover, the open -circuit voltage curve of the bronze sample is a change characteristic of first increasing, then slowly decreasing, and then increasing after fluctuations, which indicates that the corrosion rate of the bronze sample shows a trend of first increasing, then slowly decreasing, and then increasing. This trend may be that the corrosion products in the bronze reduce the contact area between the surface of the bronze and the corrosion medium, and form a passivation film with protective properties, thereby decreasing the corrosion rate, which also verified by the resuts of Tafel and EIS curves. However, the appearance of Cu2(OH)3Cl will accelerate the corrosion rate at the final corroiosn stage. The experimental phenomena and conclusions of t his study can provide a theoretical basis for the corrosion of ancient bronzes and provide support scientific basis for selecting appropriate protection strategies.

Selective corrosion is a common phenomenon observed in ancient high -tin bronze artifacts. The bronze samples from Shandong Province were analyzed by metallurgical microscope, and scanning electron microscope energy sp ectrometer (SEM-EDX). This analysis revealed that α -phase preferential corrosion is more prevalent in bronze mirror samples, whereas δ -phase preferential corrosion is more common in other types of bronze samples. Notably, both types of corrosion coexist in a few samples. The surface of antique bronze mirrors is typically smooth and susceptible to oxygen absorption corrosion in soil, seawater, and the atmosphere. In contrast, the surface of other types of bronze is typically rough, and occlusion cell corrosion is prone to occurring at surface defects. The solution within the occluded cell will be markedly acidic due to the hydrolysis of metal ions, and the acidic conditions may potentially reverse the α and δ phases. The results of the simulated corrosion test proved that bronze corrosion starts from the α-phase in an environment with low acidity and alkalinity and from the δ -phase in a strong acid condition. The δ -phase in the occlusion cell is the anode, which undergoes an oxidation reaction to produce copper ions, and the α-phase is the cathode, which undergoes a reduction reaction to produce pure copper grains. Because of the slow diffusion of ions in the electrolyte solution, the current inside the corrosion cell is intermittent due to concentration polarization, and a twin-crystal structure sometimes appears in the generated copper grains.

At present, there are many studies on the corrosion of iron cultural relics related to humidity. However, studies on the combined effects of oxygen concentration and humidity are scarce. The threshold of oxygen concentration to prevent corrosion is unclear, and it is urgent to clarify the quantitative relationship between corrosion rate and humidity/oxygen concentration. This study simulates the corrosion deterioration of rusted iron sheets under different relative humidity and oxygen content through orthogonal experiments. It adopts a combination of active and passive methods for active regulation of oxygen content and passive regulation of relative humidity in a flexible sealing bag. The oxygen content is set at 0.1%, 2%, 5% and 21% respectively, and the relative humidity is set at 10%, 20%, 30%, 40%, 50% and 60% RH respectively. The experiments show that the risk begins to emerge at 20% RH, but the risk is not significant at 20%~30% RH. The risk gradually increases at 40%~50% RH, while the risk significantly increases at above 60% RH. At a relative humidity of 10% RH, rusted iron sheet samples can remain stable and will not be affected by oxygen concentration. Therefore, for the preservation and display of iron cultural relics, relative humidity plays a decisi ve role in the corrosion deterioration of iron cultural relics, and is also an environmental indicator that needs to be prioritized for control in preventive protection. Passive regulation can be adopted to ensure the stability of iron cultural relics in a n environment with RH < 10%, and there is no need to control oxygen.

Bronze artifacts are subjected to various environmental factors during the prolonged burial process, resulting in a continuous corrosion process and the formation of a corrosion layer on their surfaces with a highly complex structure. This layered corrosion structure can vary depending on factors, such as the burial environment, the alloy composition of the bronze, and the casting microstructure. Different corrosion structures can exhibit distinct protective or detrimental effects on the metallic substrate of bronze objects. Therefore, studying the corrosion structure of bronze artifacts is crucial for assessing their stability and evaluating their preservation condition. This study first summarizes the main types and gen eral patterns of layered corrosion structures in bronze artifacts based on the literatures [1-3]. Then bronze artifacts excavated from Yejiashan Cemetery, Suizhou city, Hubei province, were investigated as a case study. The corrosion structures of the bronz e artifacts from Yejiashan were examined using optical microscopy, scanning electron microscopy -energy dispersive X-ray spectroscopy, Raman spectroscopy and X -ray diffraction. The results indicated the presence of two types of corrosion structures. Type I corresponds to a four-layered structure including an external layer, a non -metallic layer, an altered layer and an intergranular corroded layer, with the original surface preserved. The thickness of the non-metallic layer ranges from 8 to 57μm,and the pseudocrystals of the alloy can be observed on the surface. The main components of this layer are tin oxide and some copper salts. In the altered layer, the α phase corroded preferentially and (α+δ) eutectoid was preserved. Type II consists of two layers with a light green outer layer and red-brown or green and blue inner layer. The original surface has been destroyed. The major corrosion products include tin oxide, malachite, azurite and cuprite. The formation mechanisms of the two types of corrosion structures are also discussed.

Underwater ancient shipwrecks usually contain numerous wood/iron assemblies, which will face a high risk of further deterioration after excavation as environmental conditions change. It is necessary to evaluate the long -term corrosion behavior of iron in wood/iron assemblies for further study of restoration and conservation. In this paper, an iron spike, embedded in wo od from a 70-year-old ship hulk, was chosen for morphology and structure investigation. This study employed multiple analytical techniques: Ultra -Depth 3D Microscope for morphology analysis, SEM-EDS for elemental distribution, XRD for crystalline phase ide ntification, and Raman microspectroscopy for phase identification, distribution, and quantification. The morphological analysis revealed a multi-layered corrosion structure composed of three distinct layers characterized by different textures and colors, and the surrounding wood fibers gradually degraded until being entirely replaced by corrosion products. Phase identification and elemental analysis indicated that the corrosion rusts formed multi - phase mixed layers, which include (1) Internal chloride-rich layer(300–500 μm), which is non -continuous and contains β -Fe2(OH)3Cl, Ferrihydrite, and β -FeOOH. (2) Intermediate layer (400 –600 μm), which is thicker and composed of α -, β -, and γ - FeOOH, γ-Fe2O3, and Fe 3O4. (3) External sulfur -containing layer (20–50 μm), which is continuous and primarily consists of α-FeOOH and α-Fe2O3. Phase distribution and quantification demonstrated that all layers are heterogeneous, with a significant presence of highly reactive phases like iron( III ) (oxyhydr)oxides. This interface corrosion evaluation of the wood/iron assembly serves as a reference for future research on the conservation and restoration of salvaged ancient shipwrecks.

In order to further study the different rust forms of iron relics, in situ analysis of the rust state of six iron objects unearthed in Hubei province was carried out by means of ultra -depth of field microscope, metallographic microscope, scanning electron microscopy-energy spectrometer and micro-Raman spectrometer. The results show that the rust of iron relics can be divided into two categories: 1) the original form of the general iron artifacts is clearly distinguishable. It’s rust usually consist of iron oxides and C, with the microstructure of "trace image". 2) The origina l shape of the wrought iron ware is destroyed by the rust layer. The rust may consist of α -FeOOH, Fe3O4, α-Fe2O3, β-FeOOH and so on, while without "trace image" in the microstructure. The existence of a large amount of cementite and graphite in cast iron is an important reason for the remaining "trace image" structure in the rust layer and the preservation of the original form of the ware. Type I rust generally retains the original morphology of the objects, which can be preserved if it’s harmless. Type I I rust often destroys the original surface of the objects, leading to difficult to identify their shape and patten, which need to be removed including harmless rust.

Wooden shipwrecks submerged in underwater environments are susceptible t o physical and biological corrosion. This study investigates the microscopic morphology and structural composition of barnacles and the wooden surface of the Yangtze Estuary II shipwreck. Analytical techniques, including optical microscopy (OM), scanning e lectron microscope equipped with an energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD), X -ray photoelectron spectroscopy (XPS), Fourier infrared transform spectroscopy (FTIR) and photoluminescence spectroscopy (PL), were employed to analyze the corrosion processes. The findings have unveiled a distinct pattern of black corrosion, prominently concentrated within the interface region where barnacles attach to the wooden shipwreck. This corrosion primarily consists of FeS, FeS 2 and Fe3S4 and exhibits a notable tendency to expand along the wooden surface to interior region. Additionally, a striking ultraviolet fluorescence phenomenon emanates from the barnacle cement within the adhesion region of barnacles and the wooden surface. This observation has led to the hypothesis that the origin of this black corrosion is intricately linked to the barnacle cement, its role in biological corrosion, and subsequent biomineralization processes. To conclude, this study provides an intricate account of the micro bial corrosion process influenced by barnacle cement in the context of the wooden shipwreck. The research findings offer valuable insights that can serve as a point of reference in identifying the sources of disease and implementing protective measures for waterlogged wooden cultural relics.

Plate iron is an ancient salt making tool, and also is a typical representative of large -scale iron cultural relics. The plate iron unearthed in Nantong has severe corrosion diseases. For such relics, the stress corrosion caused by self-weight and the surroundings is catastrophic. In this work, the corrosion products of seven unearthed plate iron relics in Nantong were analyzed, including composition, structure and morphology. Fem simulative analysis was also conducted based on 3D scanning and display form. The corrosion property and reasons for plate iron relics under multiple factors were comprehensively discussed, in order to provide useful references for the scientific protection and preservation of such cultural relics. In short,the studies show that stress corrosion is one of the most harmful forms of corrosion for large iron cultural relics. Once it exists, it is necessary to strengthen prevention and take timely protective measures. From a mechanical perspective, it is necessary to eliminate or reduce stress by selecting large areas or multiple points that are parallel or nearly parallel to the horizontal plane and symmetrical about the center of gravity for support; From the perspective of the medium, a low humidity or oxygen free environment is the best solution; From the perspective of cultural relics, corrosion inhibition and sealing treatment should be carried out while dechlorination, removal or transformation of unstable rust, in order to improve their ability to resist the environment.

The corrosion of cultural relics refers to the reactions that occur between materials and their environment, leading to gradual destruction and degradation. The weathering and aging of cultural re lics are also considered forms of corrosion. While corrosion is usually associated with metals, non -metallic relics are also susceptible. Items such as the painted figurines, earthen sites, and stone artifacts at Emperor Qinshihuang's Mausoleum Site Museum undergo corrosion, weathering and aging. Therefore, we have outlined the analytical and experimental methods for the corrosion of cultural relics to lay a preliminary foundation for the study of the corrosion of non - metallic relics in museums. According t o the materials of cultural relics collected and unearthed by the Qin Mausoleum Site Museum, non -metallic cultural relics that are prone to corrosion mainly include pottery, jade and stone artifacts, and earthen sites. The corrosion process of these non -metallic relics can be detected through various analytical methods. Raman analysis can be used to identify the molecular structure of materials or for chronological analysis. This article aims to comprehensively understand and explore the mechanisms, conditi ons, and conservation needs of cultural relic corrosion by integrating and sorting out various analysis and experimental methods. It proposes a possible normative research method system for the Qin Mausoleum Site Museum to conduct research on non-metallic cultural relic corrosion, aging, and weathering.

The Yuquan Iron Pagoda is one of the famous ancient buildings in China, the corrosion of its surface has always been an important topic in the protection of cultural relics. In order to effectively delay the corrosion of the Pagoda and ensure its long-term stability, this study aims to screen out the corrosion inhibitor suitable for the surface anti-corrosion of the Pagoda. In the article, chemical testing methods such as weightlessness experiment, scanning electron microscope -energy spectroscopy, and laser Raman instrument were used to analyze the characteristics of different cast iron specimens before and after corrosion inhibition, such as film -forming morphology, thickness, and composition, after being immersed in 3.5% (wt.%) NaCl solution for 168 h. Additionally, the corrosion resistance of cast iron specimens before and after corrosion inhibition was tested by combining electrochemical polarization curves and impedance analysis. The results showed that 4# corrosion inhibitor had the highest corrosion inhibition efficiency (94.64%). It could react with the iron matrix to form a stable five-membered cyclo-chelate (average film thickness was 51.92 μm), and the film-forming material was adsorbed on the surface of the cast iron specimen in the form of cluster flocculent to stop the corrosion of cast iron. The magnitude of the dimensional passivation current of the cast iron specimens with 4# corrosion inhibitor added was reduced by about 3 orders of magnitude compared to that of the blank samples, and the corrosion resistance was significantly improved. The modal value of Z after 4# corrosion inhibitor pre -filming was much higher than that of the blank specimen and other corrosion inhibition systems both at the low -frequency end and the high - frequency end. Furthermore, the Rp value of 4# corrosion inhibitor in the electrochemical impedance fitting circuit diagram was the largest (Rp=180600), which further indicated that the corrosion reaction of the cast iron specimen with the addition aAuthor Introduction: Xuegang Liu (1985 -), male, associate professor, graduated with a PhD in Materials Processing Engineering from Sun Yat sen University in 2016, and currently works in the Cultural Relics Protection Engineering Department of Jingzhou Conservation Center. His research focuses on the protection and restoration of inorganic cultural relics such as bronze, iron, gold and silver, stone, dental and horn artifacts, ancient ruins and tombs. E-mail: liuxuegang705@163.com. of the 4# corrosion inhibitor was more difficult to carry out. Therefore, the corrosion inhibition of 4# corrosion inhibitor had the optimal effect. Through a series of experiments, this paper analyzes the protective effect of different corrosion inhibitors against corrosion on the surface of the simulated cast iron specimen of the Pagoda, which provides a scientific basis for the protection of the Yuquan Iron Pagoda.

Desalination treatment is a key step in the protection of ancient iron artifacts. For iron vessels with high soluble salt content, desalination treatment must be carried out as soon as possible. For iron vessels with low soluble salt content and no threat of salt damage, desalination is not necessary. Therefore, it is necessary to conduct research on the threshold of soluble salt content for whether ancient ironware needs to be desalinated. This article quantitatively characterizes the content of soluble salts in iron equipment using the Engel 138 Bresle salt detector, and studies the critical content of soluble salts that need to be desalinated through simulation experiments. The Elcometer 138 Bresle salt detector is easy to operate, accurate and reliable, and can be used for testing the degree of salt damage to other cultural relics, with good application and promotion prospects.

This paper reviews the internal and external causes of atmospheric corrosion of iron cultural relics, including the nature of iron itself, the production process of iron cultural relics, and the in fluence of the external environment. The mechanism of atmospheric corrosion of iron cultural relics has been analyzed and explained in terms of both chemical and electrochemical corrosion. The physicochemical properties of six atmospheric rust products of iron cultural relics are summarised. These rusts are classified according to the criteria of harmful and harmless to iron cultural relics. Methods of restoration and conservation of iron cultural relics are summarised. This paper is inspiring and helpful for the restoration and conservation of large outdoor iron cultural relics.

Indoor air quality in museums is important for protection and conservation of artifacts. In this study, four museums located in different regions of China were selected, including Beijing, Qingdao, Wuhan, and Guangzhou. To investigate the museum environment, indoor air and dust samples were collected and analyzed in 11 rooms. Temperature and humidity were monitored continuously. Simulated and archaeological iron block samples were placed at each sampling location, and their mass change were measured periodically to evaluate corrosion levels. Over 120 volatile and semi-volatile organic pollutants were detected and quantified, including carbonyls, organic acids, phthalates, polyaromatic hydrocarbons, organophosphates, pesticides, etc. Among them, more than 60% of pollutants had a detection frequency over 50%. The results indicated that organic pollutants were widespread in museums. Ranking of environmental factors were conducted based on both the results of multiple methods of statistical analysis, and chemical properties of pollutants. As a result, many chemicals may influence iron corrosion, most of them were seldomly reported before. The reaction mechanism and quantitative correlation between pollutants and iron artifacts were investigated. Cyclohexanone was found to be catalyzed by iron to form organic acids. For acetic acid, 10 mg/m3 was a safe value of concentration for iron samples under 50°C and 90%RH. Our work provided more understanding of pollutants in museums and their relationship with iron artifacts. The findings guarantied further research on the environmental impacts on cultural heritage artifacts.

The application of new corrosion inhibitors in the conservation of metallic cultural relics has been limited, primarily due to the lack of standardized testing and evaluation methods, as well as the absence of long -term application data on actual artifacts. The formulated standard, 'Requirements and Evaluation Methods for Iron Cultural Relics Inhibitors' specifies the applicability and effectiveness requirements for corrosion inhibiting materials of iron relics and describes the methods for their evaluation. This standard provides a set of standardized testing and evaluation methods for assessing the performance of corrosion inhibitors for metallic relics. The standardized evaluation data can not only serve as a qualification criterion for the application of new corrosion inhibitors in the conservation of metallic relics but also facilitate the gra dual establishment of a database on the applicability, effectiveness, and long-term performance of corrosion inhibitors. The development of this database will allow for more targeted corrosion mitigation strategies for different types of metallic relics, a nd, with the support of materials genomics research methods, will further promote the research and development of new conservation materials for cultural heritage protection. In the future, the development of functionalized coating systems with self -warning and self -repairing capabilities, through methods such as loading corrosion inhibitors and carbon quantum dots into microcapsules, will be a key direction in the conservation of metallic cultural relics.

In recent years, the techniques for evaluating the stability and conservation effectiveness of iron artifacts have progressively evolved from non -in situ, localized, destructive, and qualitative methods to in -situ, comprehensive, non -destructive, and quantitative approaches. This study utilized Macro X -ray Fluorescence (MA -XRF) scanning imaging, oxygen consumption measurement, and in -situ electrochemical impedance spectroscopy (EIS) techniques to monitor the corrosion deterioration rate and assess the conserv ation effectiveness of an iron stirrup excavated in Liaoning Province, China at various stages before and after conservation treatment. MA-XRF scanning imaging provided insights into the distribution of elements on the artifact's surface, which is crucial for determining the necessity of desalination and for guiding targeted sampling analyses; it also reflected the effectiveness of desalination treatment. The oxygen consumption measurement method monitored the overall corrosion rate of the artifacts under c ertain environmental conditions, with changes in the corrosion rate across different conservation stages indicative of the treatment's effectiveness. The in-situ EIS characterized the corrosion behavior of the artifact's surface in real -time, allowing for the evaluation of the mechanisms and effectiveness of corrosion inhibitors and coatings. The combined analytical results indicated that the iron stirrup was severely corroded, with rust layers rich in chlorides, exhibiting typical active corrosion such as "weeping" and the presence of akaganeite. Following conservation treatments including rust removal, desalination, inhibition, and coating, the corrosion rate of the iron stirrup gradually decreased, their stability significantly improved, and the effectiveness of the conservation treatments was markedly demonstrated.

Silk is a natural material that has been used for over 5,000 years to produce numerous precious textiles. Silk fiber is a polymer composed of sericin and fibroin, which are two types of proteins consisting of C, H, O, N, etc. Before weaving, raw silk is normally subjected to degumming in which the majority of silk sericin has been removed. The degummed silk contains mainly fibroin which composed of amino acids that fold into antiparallel β-sheets crystallites and an amorphous region. The unique structure makes silk one of the most sensitive natural fibers that is easily influenced by deterioration agents. As a result, only a small amount of ancient silk has survived after long-time burial. Therefore, it is of great importance to investigate the degradation behaviors of ancient silk by assessing the ageing and evaluating the stability. To date, the characterizations of silk degradation are widely studied. The focus shifts from m orphological level to molecular level of silk by employing various methods. However, most reported works focused mainly on evaluating the property changes upon the variation of structure and composition of silk. There remains a lack of systematic research on measuring and quantifying the degradation of silk with effective ageing indicators, in order to accurately determine the deterioration status. In this paper, the deterioration behaviors of two ancient silks were investigated in comparison with the mode rn silk. XRD, XPS, EPR and 13C CPMAS NMR were employed to measure the crystallinity, oxidation and carbonization degree, variation of amino acid content and content of random coil. The results and findings provided numerical ageing indicators for assessing the deterioration status of ancient silk. The research would be beneficial to determine the structure change and stability of silk, and further provide scientific evidence for the conservation of ancient silk.

The study of the degradation phenomena affecting bronze artworks exposed to outdoor atmospheric corrosion i s fundamental to develop tailored preventive conservation strategies. The characterization of the corrosion products and the assessment of the atmospheric and microclimatic parameters affecting the material/environment interaction allows obtaining importan t information on the conservation state of the artworks and on the strategies to be implemented to ensure their safeguard. In this study an on -site monitoring campaign has been carried on several bronze artworks, of the Gori Art Collection, a private collection of environmental art exhibited at the Fattoria di Celle, Santomato (Pistoia, Italy). The on site monitoring campaign started in 2019 and it is still in progress by employing a multi -analitycal approach. At a first visual examination, the bronze artworks showed different corrosion morphologies related to the different exposure conditions to atmospheric agents; galvanic corrosion due to coupling between the bronze artworks and the steel grips used for their positioning was observed too. Electrochemical Impedance Spectroscopy (EIS), XRF and Raman spectroscopy allowed to determine the composition of the metallic alloys and of the corrosion products, as well as to assess the electrochemical behaviour and the protective effectiveness of the corrosion patinas. Moreover, it was possible to highlight the surfaces that were more exposed to the aggressive agents present in the atmosphere and to the washing action of the rain. A 3D photogrammetry survey is also performed to create a complete documentation of the ar tworks. The results of the monitoring campaign highlight the advantages of the proposed approach, and allow to discuss the challenges still open in the development of tailored safeguard methodologies for outdoor bronze artefacts.

青铜器“粉状锈”作为青铜器常见的病害,指的是在青铜器表面出现的一种类似粉末 状的锈蚀物,这种锈蚀物主要由氯离子引发,通过电化学腐蚀过程在青铜器表面及内 部不断蔓延,导致金属基 体逐渐被侵蚀。粉状锈不仅破坏了青铜器的表面纹饰和铭文, 还可能引发更严重的“病害循环”,即锈蚀产物中的氯离子继续作为新的腐蚀源,加速青 铜器的腐蚀过程。因此,采取有效措施对“粉状锈”进行治理和预防是做好青铜器长期稳 定的重要保证。 本文针对青铜器 “粉状锈”的基本性能,结合青铜器本体的保存状态,在全面梳理 “粉状锈”发生、发展机理的基础上,提出了基于基于表面处理与渗透加固的青铜器 “粉 状锈”防护处理措施。首先采用自剥离除锈凝胶清除青铜器表面的 “粉状锈”及其他附着 物,恢复青铜器的原始面貌;其次,采用金属配合物溶胶对青铜器“粉状锈”部位进行渗 透加固处理。金属配合物加固剂能够渗入“粉状锈”内部,形成稳定的化合物层,从而增 强青铜器的力学性能与耐腐蚀性。同时,加固剂还能在青铜器表面形成层保护膜,有 效隔绝外界环境的侵蚀。这些措施不仅有效地遏制了“粉状锈”的蔓延与恶化,而且还在 一定程度上恢复了青铜器的原始面貌与内在价值。此外,也探索了采用低温等离子体 对青铜器“粉状锈”实施原位转化实验,评价了低温等离子体对含氯 “粉状锈”的原位转化 效果,提出了低温等离子体技术提升改进的发展方向,期待在科技进步的推动下,能 够探索出更多科学、高效的青铜器保护 技术与方法,为中华文明的传承与发展贡献更 多力量。

In contrast to microbiologically influenced corrosion (MIC), biomineralization can inhibit the corrosion of metal substrates by forming dense and uniform biomineralized films with barrier effects against corrosion. Biofilms as a key role in the biomineralization process, can be i mproved by extracellular electron transfer (EET) which may introduce corrosion process. This study reports the effect of EET on biomineralization mediated by Shewanella putrefaciens in damaged coatings under different carbon sources (100, 75, 50, and 25 wt %) 2216E conditions. The results showed S. putrefaciens was able to obtain energy from metal surfaces to support metabolism via EET when the carbon source was insufficient. Under these conditions, although EET can promote the enrichment of bacteria on the coating scratches, the corrosion process was accelerated, and generated Fe 2O3 and FeOOH corrosion products whereas biomineralization was inhibited. Meanwhile, the decrease in pH value of medium means the microbial metabolic pathways turn from aerobic respiration to other metabolic pathways. When the environment had sufficient carbon sources, aerobic respiration was the main pathway supporting the metabolism of S. putrefaciens, and biomineralization dominated and showed corrosion -inhibition effects. The EIS results also revealed that biomineralization was most significant in the 75% carbon source medium after 7 days of incubation.

In the marine environment, microorganisms like bacteria rapidly adhere to the substrate surface and result in the microbiologically induced corrosion (MIC), contributing to about 20% of total corrosion loss in the world. Various of antibacterial agents are used to inhibit the adhesion of bacteria. However, residual dead bacteria on the surface still interact with surrounding live bacteria with a long -term effect[1]. In this study, the interaction between the surface decorated with dead lactobacillus rhamnosus (LGG) and planktonic live Pseudomonas aeruginosa (PAO1) was explored. DHM and cantilever modulated atomic force microscopy (CM-AFM) were both used to observe the 3D motions, adhesion, biofilm, and responsive behaviors of P. aeruginosa on dead LGG coated surfaces, which were treated with different sterilization methods. RNA-seq and metabonomics were used to explore the molecular mechanisms. Both the presence of live and dead LGG leads to the downregulation of the chemotaxic pathway and the upregulation of the flagellum assembly pathway, which decreases the frequencies of flick and reverse motions and increased the velocity and dispersion of the swimming PAO1 near the dead LGG surfaces. Compared with live LGG, the adhesion force between P. aeruginosa and dead LGG are lower accompanied by more downregulation of the biofilm formation pathway. This study proved that the inhibition effect of dead probiotics originated from the release of cellular lysate [2]. The rate of release depends on the integrity of the membrane, which results form the sterilization method This work provides a novel strategy for designing antifouling materials.

Sulfate-reducing bacteria (SRB) were recognized as significant contributors to microbiologically induced corrosion (MIC). D eveloping effective, economical, sensitive, and specific detection methods for SRB was crucial for understanding microbial corrosion mechanisms and for early monitoring. In this paper, a novel dual-mode biosensor was successfully constructed for detecting the DsrA gene associated with SRB. The biosensor utilize d gold nanoparticles (AuNPs) as nanoenzymes and methylene blue (MB) as an electron acceptor, enabling electrochemical and colorimetric self -powered detection. The AuNPs/Cu -TCPP(Fe) composites were synthesized using a hydrothermal method and characterized through various techniques, including SEM, TEM, XRD, FT-IR, UV-Vis, and XPS, to verify morphology, structure, and composition. Nanozyme activity experiments demonstrated the glucose oxidase-like activity of the material. Characterization of the modification processes for the anode with the composite material and the cathode with DNA nanostructures was performed using CV, LSV, DPV, and EIS techniques to evaluate the electrochemical behaviors. Under optimized conditions, open circuit potential and RGB Blue values were employed as signal responses for the electrochemical and colorimetric modes, respectively. Compared to previously reported sensors for SRB DNA detection, this biosensor demonstrated superior detection performance with stability, specificity, and reproducibility. Notably, the biosensor achieved a detection range in the target concentration of 1 fM to 10 nM, with detection limits at 0.33 fM in electrochemical mode and 0.4 1 fM in colorimetric mode. Additionally, the biosensor effectively detected extracted SRB DsrA gene fragments from real seawater samples, showing a broader detection range and lower detection limits compared to traditional methods such as agarose gel electrophoresis and real-time fluorescence PCR. In conclusion, this dual-mode self -powered biosensor provide d a promising alternative for sensitive and specific detection of SRB, highlighting its potential practical application value in SRB detection.

Microbial corrosion based on extracellular electron transfer (EET) has been widely studied on iron-based metals, however, it is still scarce for aluminum alloys. In this study, the corrosion beh avior of a novel isolated marine actinomycete, Nocardiopsis dassonvillei, against 5083 aluminum alloy (AA5083) was systematically evaluated. The results proved that N. dassonvillei biofilm accelerated AA5083 corrosion by increasing the dissolution of oxide layers through chloride accumulation, preventing the re-passivation through oxygen depletion. On metal substratum with the defected oxide film, N. dassonvillei accelerated Al dissolution by facilitating inward EET with phenazine as an electron shuttle between metal surface and bacterial cells.

Methanogens are one of the main species that cause metal corrosion in pipelines via forming biofilm, which greatly reduce the role of corrosion inhibitors and thus increase their dosages. D-amino acids can inhibit the formation of biofilm, which might be an effective means to improve the conventional corrosion inhibitors. However, little literature reported the synergistic effects of corrosion inhibitors and D-amino acids on methanogens -mediated corrosion. Therefore, 1 -hydroxyethane-1,1-diphosphonic acid (HEDP) was chosen as a typical corrosion inhibitor and D-Phenylalanine (D-Phe) as a D -amino acid to evaluate their roles in corrosion caused by Methanosarcina barkeri (M. barkeri ). D -Phe and HEDP can synergistically inhibit microbiologically influenced corrosion, reducing corrosion rate by 89.66% and effectively mitigating corrosion on carbon steel surfaces. Electrochemical tests showed that HEDP and D - Phe can retard the cathodic reaction and reduce the corrosion rate, and CLSM analysis showed that HEDP and D -Phe can reduce the protein content in biofilm, which was only 2.44% of that in the blank group. Transcriptome analysis further revealed the molecular mechanism by which HEDP and D-Phe alleviated corrosion. The addition of HEDP and D -Phe resulted in the down -regulation of the genes MSBRM_RS06090, MSBRM_RS13790, and MSBRM_RS13820, which are related to extracellular protein secretion and biofilm formation, thus making it difficult for M. barkeri to aggregate and form biofilms. This study provides a new approach to enhance conventional corrosion inhibitors, mitigate microbiologically influenced corrosion and alleviate eutrophication of water bodies.

With the continuous growth of the global economy and incre asing attention to marine resources, the development and breakthrough of marine engineering materials have become crucial for human exploration of the marine. Copper-nickel (Cu-Ni) alloys are extensively applied in critical components such as seawater intake pipes, seawater pumps, and seawater coolers, ensuring the efficient operation of engineering facilities[1]. However, Cu-Ni alloys face various types of corrosion challenges in marine environments, particularly the issue of corrosion perforation which is not uncommon. Once the piping system of equipment ruptures due to corrosion, it poses a serious threat to the safety of personnel on board. Therefore, studying the corrosion behavior of Cu-Ni alloys in marine environments holds significant importance. This paper concentrated on the multifactor-coupled corrosion mechanisms of Cu-Ni alloy pipelines in marine environments under actual operating conditions. Our group employed exogenous redox electron mediators and energy starvation experiments to investigate t he microbial corrosion mechanism of Ni induced by Pseudomonas aeruginosa, which belongs to the EET-MIC mechanism[2]. The MIC behavior of Cu-Ni alloy is found to be more intricate when compared to pure nickel. Recent years have seen a notable increase in ni trogen content in seawater due to the impact of marine pollutants, surpassing levels found in natural seawater. Consequently, we further explored the influence of ammonium presence in the microbial culture medium on the susceptibility of Cu-Ni alloy to MIC. This work revealed that Pseudomonas aeruginosa and ammonium exhibit an antagonistic effect, mitigated the MIC process of Cu -Ni alloy[3]. At the same time, we proposed a schematic diagram of the mechanism of ammonium to mitigate the microbial corrosion of Cu-Ni alloy caused by Pseudomonas aeruginosa. Fig. 1 Schematic diagram of the mechanism of ammonium to mitigate Pseudomonas aeruginosa induced microbial corrosion of Cu-Ni alloy

Through refining five types of pipeline steel with different Cu contents (0Cu, 0.6Cu, 1.0Cu, 1.3Cu, 2.0Cu, w%), the effects of Cu content and aging treat ment on the corrosion behavior of X80 steel in a Bacillus licheniformis environment were investigated from the perspectives of antibacterial performance, corrosion product analysis, and electrochemical behavior. The study revealed that only the 2.0Cu steel exhibited a notable antibacterial effect against Bacillus licheniformis. For rolled materials, the addition of Cu enhances corrosion resistance, but aging accelerates corrosion in Cu-containing steels. In bacterial systems, the corrosion current density of the material is lower compared to sterile systems, indicating that the microbial film offers some protective effect.

Oral microorganisms is o ne of the key factors leading to corrosion of titanium and its alloy implant materials. Currently, microbial-influenced corrosion (MIC) related to dental implant materials mainly focuses on bacteria. However, MIC associated with oral implant materials involves inherent interactions between fungi and bacteria, directly related to the formation of mixed biofilms. This suggests that fungal - bacterial interactions have potential clinical significance in MIC related to oral implant materials. In this study, we ev aluated and compared the corrosion effects of Streptococcus mutans, Candida albicans, and mixed bacteria on implant materials pure Ti and Ti-Zr alloy. The results showed differences in biofilm structure, corrosion behavior, and mechanisms between single an d mixed bacteria. The cross -kingdom interaction between Streptococcus mutans and Candida albicans enhanced biofilm maturity and acidity, providing necessary conditions for pitting corrosion. Candida albicans played a dominant role in the interaction betwee n Candida albicans and Streptococcus mutans. Furthermore, we found that the addition of Zr to titanium-based alloys improved the alloy's biocompatibility and corrosion resistance. The results of this study provide a basis for better selection and applicati on of oral titanium implant materials from the corrosion point of view, and provide ideas for evaluating the biocompatibility of oral implant materials.

Microbiologically influenced corrosion (MIC) has become one of the main causes of corrosion failure of pipes and equipment in scenarios including water in jection, hydraulic fracturing, oil and gas gathering and transportation and wastewater treatment systems in oil and gas industry. Compared with the common electrochemical corrosion caused by CO 2, H 2S, O 2, etc., microbiologically influenced corrosion has it s uniqueness, which involves the interaction of microorganisms' own life activities or metabolites with metals. Conventional corrosion test methods are no longer applicable. At present, there is no standard for MIC test method in the world. In 2020, schola rs from the United States, Singapore, Kazakhstan, Japan, Australia and Germany jointly reviewed the progress of MIC in recent 25 years, and pointed out the main problems of MIC in laboratory research methods. First, since there are no standards and recommended practices for conducting laboratory tests, each laboratory tends to use its own electrolyte formula, so the test results cannot be compared. Second, the test results cannot be verified because there is no standard to report the details of the test procedure. For example, laboratory experiments are routinely conducted in poorly described culture media that could never be replicated without additional information, particularly regarding the concentrations of growth factors. In May 2023, ISO 21055 became the first project to standardize microbiological corrosion test method focusing on oil and gas transmission pipeline scenarios and attracted the participation of experts from Germany, Italy, the United Kingdom, Japan, China, the Czech Republic and other c ountries. This project was aimed to specify a test method for MIC of oil and gas transmission pipelines, including the principle, apparatus, sources of strains, solutions, specimens, sterilization, procedure, results and report. It is applicable to MIC tes t of metals and alloys for internal surfaces of oil and gas transmission pipelines. In addition, the MIC test for metals and alloys used in downhole, water injection and similar systems in the oil and gas industry can also refer to this document. ISO 21055 is currently undergoing a CD consultation to collect comments from experts in different countries. This paper presents the CD draft of ISO 21055 and discusses the issues identified during the standardization of MIC test method.

Microbiologically influenced corrosion (MIC) is the result of microorganisms' life activities causing corrosion damages to metals or non -metals [1]. SRB had important application value for FeS produced after iron corrosion. It was widely used in catalysis, sensors, electronics, photovoltaics, and other fields [2]. Biosynthetic metal sulfides showed great application prospects on the environmental treatment against high - valence metal pollutants. However, the efficiency of biosynthesis, agglomeration during the reaction process, and the formation of the passivation layer during the reduction process were always the important factors restricting its development. This study explored the composition of the culture medium to promote the growth of highly corrosive SRB and its metabolism to produce FeS NPs. The results showed that reducing the carbon sou rce and adding electron carriers in the culture medium effectively promoted the prod12quction of small, dispersed, and loose FeS NPs in cells. At pH = 7, 24 oC and 10 min reaction time, 0.1 g/L FeS NPs produced by SRB under the conditions of 10% carbon source with 10 ppm cytochrome c medium could achieve 100% removal efficiency of 1 mM Cr(VI). Under this condition, FeS NPs could be produced by intracellular metabolism in SRB cells, and environmental factors such as pH, metal cations, and Cl - had little effe ct on the removal of Cr(VI) by this FeS NPs. The surface proteins of FeS NPs significantly enhanced its antioxidant properties. After 7 days of natural environment exposure, the Cr(VI) removal efficiency of FeS NPs was only reduced by 16% compared with the initial sample. This work provided an in-depth understanding of Cr(VI) removal by SRB biosynthesis of FeS and contributes to the widespread application of FeS in the future.

Sulfate reducing bacteria (SRB) are widely present in oil and gas industry, causing pitting co rrosion on pipeline steel. Stress corrosion cracking (SCC) often occurs in the presence of mechanical stress before pitting perforation failure, leading to economic losses and even catastrophic accidents. In this study, stress distribution simulation using the finite element method (FEM), corrosion analysis techniques and electrochemical corrosion measurements were employed to investigate the SCC mechanism of X80 pipeline steel caused by Desulfovibrio vulgaris, which is a common SRB strain used in microbiol ogically influenced corrosion (MIC) studies. It was found that D. vulgaris MIC caused sharp microcracks on an X80 U-bend coupon after only 2 weeks of immersion at 37 ° C in the deoxygenated ATCC 1249 culture medium inoculated with D. vulgaris. The X80 U -bend coupon’s weight loss -based uniform corrosion rate for the 12 cm 2 surface was 60% of that for the unstressed flat square coupon (2.3 mg cm −2 vs. 3.8 mg cm −2). This was likely because the square coupon had wide MIC pits, providing a larger effective surface area for more sessile cells (4.2× 108 cells cm−2 on square coupon vs. 2.4× 108 cells cm−2 on U-bend coupon) to attach and harvest more elec trons. An SCC failure occurred on an X80 U -bend pre-cracked at the outer bottom after a 6-week immersion in the D. vulgaris broth. Apart from MIC damage, this could also be because D. vulgaris metabolism increased the availability hydrogen atoms on the ste el surface, and promoted the diffusion of hydrogen atoms into the metal lattice, thus increasing the brittleness of the steel.

The composition of the biofouling layer is complex in the ocean, and its formation process is mainly dominated by the preferential a ttachment of microorganisms, which then attract the spores or larvae of plankton. Finally, large fouling-organisms such as barnacles and mussels further adhere, through internal cooperation and competition, forming the fouling biofilms with complex structu res. However, there has been little research on the effect of different types of organisms in the fouling layer on metal corrosion until now. Thus, the effects of Phaeodactylum tricornutum (a diatom with obvious fouling characteristics) and its symbiotic bacterium Bacillus altitudinis on magnesium alloys used in marine environment were studied in this paper. It was found that algae could not grow on the magnesium matrix and could not form algal fouling biofilm in the short term. However, it is surprisingly found that the bacterium survived in such a harsh condition with high alkalinity, which did not accelerate the corrosion of Mg. Instead, the corrosion was even be suppressed by one order of magnitude. The suppressed corrosion could be ascribed to depositio n of biofilm mainly made of EPS, and up-regulated metabolites a crystal MgNH4PO4 · 6H2O layer, formation of a bacterial in the biofilm. Based on this, further research found that the algae symbiotic bacteria can effectively improve the anode efficiency of magnesium as a sacrificial anode material, which can be up to 79%.

Based on the potential bactericidal properties of borate, we synthesized controlled-release borate (CRB) as a novel biocide to inhibit microbial proliferation in a recirculating cooling water system (RCS). Our results showed that the inhibition rates of CRB on the isolated bacteria and algae reached 80.4 -84.0% and 55.0%, respectively. CRB achieved a complete release of antibacterial factor-boron in 20 days in the simulated RCS. The number of heterotrophic bacteria ( HB) was reduced to 3.8× 103 CFU/mL, which met the requirement of the Chinese national standard GB/T 50050-2017 (< 1× 105 CFU/mL). CRB achieved a significant reduction of the dominant species, namely, Pseudomonadota and Chlorophyta. The algae-inhibiting behavior of CRB was mainly reflected in the inhibition of nucleic acid synthesis and photosystem II photochemical activity. Functional annotation of differentially expressed genes revealed that the downregulation of the “photosynthesis -antenna proteins” and “large/small subunit ribosomal protein” pathways was the main inhibitory behavior of CRB; reverse transcription real -time quantitative polymerase chain reaction verified this result. Additionally, the expression of antioxidant enzymes and cell volume-related genes coincided with phenotypic changes. Moreover, CRB exhibited excellent scaling and corrosion inhibition properties. The determination of the biocidal mechanism of CRB in this study will help enhance the practical application of multi -functional water treatment agents in RCS.

With the rapid advancement of aerospace technology, microbial -induced corrosion in space environments has become a growing concern. To uncover the long-term potential risks posed by microbial corrosion under space conditions, this report systematically reviews three major research methods: ground -based experiments, simulated microgravity experiments, and in-orbit experiments. Our recent work focuses on the in teraction mechanisms between aerospace materials, including aluminum alloys, magnesium alloys, and printed circuit boards, and microbes under different gravity conditions. The study shows that microbial growth and metabolic characteristics, such as biofilm structure, ultrastructure, and metabolic byproducts, exhibit significant variations across different gravity environments, altering the interaction interface between microbes and materials, which in turn affects corrosion and degradation behavior. Notably, in the long-term operation of space stations, microgravity changes mass transfer and surface liquid film distribution on material surfaces, leading to differentiated microbial growth behaviors and more pronounced lateral and vertical corrosion propagatio n. As a result, conducting authentic, long -term in -orbit experiments is essential for the accurate life prediction of aerospace materials and the development of new materials, providing critical scientific insights and technical support.

Microbiologically influenced corrosion (MIC) [1] induced by sulfate reducing bacteria (SRB) is a common and tricky problem in pipelines. Presently, biocides are used generally to inhibit MIC in offshore oil and gas fields [2]. The concentration for biocide application should be determined according to the actual situation of the site. Excessive dose use of a biocide may lead to environment pollution and economic losses in industrial production and transportation systems. While inadequate use can not protect steels effectively, it sometimes may even cause more severe corrosion than normal. The 2,2 -dibromo-3-nitrilopropionamide (DBNPA) is a biodegradable biocide widely used in oil and gas pipeline maintenance. However, the practical application generally faces the confusing problem that the effective dose of b iocide for MIC prevention is unclear. In this study, the effect of different concentrations of DBNPA on the corrosion behavior of X80 pipeline steel in the presence of SRB has been investigated. The results show that the corrosion rate was reduced by 20.2 %, if DBNPA was supplied at 150 ppm. However, the corrosion rate increased by 1.5 times (p = 0.002) at 1000 ppm DBNPA over the one without DBNPA addition, although scanning electron microscope (SEM) images show that sessile SRB cells were almost all killed with 1000 ppm DBNPA addition. Further chemical composition analysis shows that a high concentration of DBNPA might attack the steel and cause a chemical corrosion of steel. Thus, a comprehensive evaluation is needed to determine the proper dosage of bioci des in actual applications.

Dissolved oxygen has a very complex effect on microbial corrosion in the ocean. In this paper, the impact of dissolved oxygen on the corrosion behavior of X70 steel in seawater environments with and without P. aeruginosa was investigated by electrochemical testing, surface morphology observation, corrosion weight loss analysis, and elemental anal ysis of corrosion products. The results showed that the uniform corrosion rate in the anaerobic P. aeruginosa seawater environment was lower than that in the sterile seawater environment, but the local corrosion was severe, with the maximum width of the pi tting crater being 578.38 μm, and the maximum depth being 49.95 μm. P. aeruginosa formed a biofilm on the surface of the steel substrate, and the presence of the biofilm promoted local corrosion. The addition of dissolved oxygen accelerated the overall corrosion of X70 steel by marine P. aeruginosa, with a maximum corrosion rate of 45.62 mpy after 7 d of immersion, which was about two orders of magnitude greater than the corrosion rate of P. aeruginosa under anaerobic conditions. The presence of dissolved oxygen accelerated the metabolic activity of P. aeruginosa, promoted the redox reaction of the steel matrix, and produced a large number of metal oxide films and microbial films, which were doped with microbial films to form a composite product film, and th e metal oxides mainly consisted of Fe 3O4, FeOOH, and Fe2O3, and the incorporation of dissolved oxygen greatly influenced the overall corrosion of P. aeruginosa on the X70 steel uniform corrosion and also promoted local corrosion to some extent.

Marine biofouling and microbiologically influenced corrosion, caused by a wide variety of microorganisms and corrosive species, have been multi-trillion-dollar-a-year problems. The development of multi-functional materials to tackle those challenges has been a long-standing quest in marine services. Aluminum-based high-entropy alloys (HEA) are promising engineering materials, however, their applications are limited given the poor anti-corrosion resistance in marine environments. Herein, we designed AlxCoCrCuFeNi HEA (x = 0, 0.1, 0.3, and 0.5, molar ratio) with superior marine anti-biofouling and anti-corrosion performance. The effects of Al contents on the AlxCoCrCuFeNi corrosion resistance were unveiled by analyzing microstructure, antibiofilm properties, antifouling properties, and passive film. The effect of released copper ions leads to minimizing adherence of biofilms upon the material surfaces. In particular, Al0.3HEA exhibits the highest corrosion resistance, owning to an Al2O3-Cr2O3 enriched passive film to hinder the dissolution of the passive film. This work provides a systematic strategy for anti-biofouling and anti-corrosion HEA materials that can serve a great range of applications in marine engineering.

Numerous tests have demonstrated the impact of microbiologically influenced stress corrosion (MISC), but the dynamic corrosion process and its influencing variables are still unclear. In this work, corrosion monitoring sensors were used to gather data on materials, microorganisms, and env ironmental factors. Based on the random forest model, the significant effects of environmental temperature, the quantity of bacteria, kernel average misorientation (KAM), low angle grain boundary (LAGB) and prior austenite grain boundary (PAGB) on MISC wer e analyzed. The findings demonstrate d that, under various loads and structures, the corrosion monitoring sensor can accurately depict the dynamic corrosion process of Bacillus cereus on X80 steel. Following base metal (BM) with stress, coarse -grained heat - affected zone (CG), and BM, the cumulative corrosion quantity of CG with stress during the test period was the greatest. The early stage of immersion was a crucial time that affects corrosion as opposed to the middle and later stages. Temperature, LAGB, and bacterial count were the primary factors influencing X80 steel without stress. The key factors in the stress instance were the quantity of microorganisms, KAM, and PAGB. This served as the theoretical foundation for the explanation of the mechanism by which that nitrate -reducing bacteria promote stress corrosion cracking. The findings will impact upcoming conservation initiatives and advance our understanding of MISC.

Sulfate-reducing bacteria (SRB) is a typical anaerobic corrosive microorganism that can reduce SO 42− to H 2S. SRB produces nanoscale corrosion products during the corrosion process and has very good application potential in the field of catalysis. This research propose d a novel biosynthesis method for MoS 2 and MoO3 complexes using cyclic voltammetry (C V) in a sulfate -reducing bacteria (SRB) medium. In this study, a standard three-electrode system was used, with molybdenum mesh as the working electrode, and SRB culture medium as the electrolyte. A linear voltage was applied using an electrochemical workstation. Subsequent structural and surface characterizations were conducted using SEM, EDS, XRD, and XPS, confirming the successful synthesis of MoS 2 and MoO 3. After optimizing the experimental conditions, the most effective degradation of MB was achieved w ith a voltage range of 0.6-1.2 V, a scanning speed of 30 mV/s, and 10 scanning cycles. The study demonstrate d the efficient degradation of methylene blue (MB) through the activation of peroxymonosulfate (PMS). The prepared material was added to 10 mg/L methylene blue solution and PMS solution, and degraded under visible light conditions. The absorbance of degraded MB solution at 665 nm was measured every 2 minutes by UV -VIS DRS spectrophotometer. The optimized conditions for MB degradation were identified a s follows: pH=6, PMS concentration of 0.4 g/L, molybdenum mesh dosage of 0.09 cm2/ml, and an incubation period of 8 days. Under these conditions, 99% of MB could be degraded within 10 minutes. Additionally, antibacterial tests confirmed the disinfection ca pabilities of the synthesized materials. The catalytic mechanism was further elucidated through ESR tests and free radical trapping experiments. This study presents a novel in -situ method for the synthesis of MoS2/MoO3, showing good prospect in environmental treatment.

The corrosion failure of marine engineering materials leads to significant economic losses and may trigger safety accidents. Traditional corrosion pr evention strategies have been hindered by their environmental hazards, complex processes, and high costs. Recently, the application of living microbes for corrosion protection has attracted much attention, but this approach is limited by the dynamic nature of microbial biofilms. Herein, we designed a bio -ink composed of sodium alginate, gelatin, and sodium lignosulfonate by screening for adhesive strength and mechanical properties. By incorporating Vibrio natriegens with strong mineralization capabilities, a living coating that exhibits excellent corrosion protection performance was developed. It was corrobarated by electrochemical corrosion tests, morphological characterization, and corrosion product analysis. Furthermore, we optimized the 3D printing param eters of the bio-adhesive coating, enabling its application in corrosion protection under special environment. This study provides a novel approach for the development of environmentally friendly, renewable, and cost -effective corrosion protection technologies based on living microbes.

Petroleum hydrocarbons present in oil -containing environme nts pose significant threats to the integrity of steel infrastructures by providing essential nutrients for microbial survival, consequently altering the microbial composition and metabolic pathways of microbial communities. To investigate potential keysto ne taxa that drive the MIC process in these environments, we employed culture -dependent methods, including metagenomic sequencing and quantitative PCR (q-PCR), to characterize the in situ corrosive microbial communities in the initial phase of our study. T he findings indicated that sulfate -reducing bacteria (SRB), often regarded as the primary contributors, are not always the predominant keystone groups. Instead, archaea including methanogens ( Methanolobus, Methanohalophilus and Methanocalculus), fungi incl uding mould ( Aspergillus, Fusarium) and yeast ( Yamadazyma), and oil - degrading bacteria ( Alcanivorax and Marinobacter), were the abundant corrosion - related members that exhibited higher relative abundances than SRB [1,2]. Furthermore, we futher explored the ir metabolic features that may attribute to corrosion by using experimental culture-dependent and microcosm tests [1,3]. The results demonstrated that petroleum hydrocarbons enhanced not only microbial oxygen respiration and aerobic hydrocarbon degradation but also nitrate reduction and anaerobic hydrocarbon degradation processes, highlighting the need to consider these microbial groups and their related corrosion-causing mechanisms in oil-containing environments.

This study assessed the phenomenon of microbial deteriorated corrosion in aircraft fuel tanks with seal failure, discovering the mechanism of sealant -aluminium alloy deterioration caused by fuel microbial contamination. Aerobic microorganisms such as Pseudomonas aeruginosa accelerate pitting corrosion of 2024T3 aluminium alloy, which was related to formation of micro-galvanic couples. The abiotic deposition of C and P elements maybe mainly affect formation of corrosion products on surface of aluminium alloy and coating components. Hydro carbon-degrading Shewanella algae accelerated corrosion of LY12 aluminium, but inhibited corrosion of 7B04 aluminium through nitrate reduction. Coating on 7B04 aluminium alloy can reduce biofilm coverage, but it still cannot avoid the deterioration effects induced by S. algae, such as pitting, swelling, and peeling. 7B04 aluminium alloy has better corrosion resistance in the fuel-water system than LY12. The combination of zinc -yellow acrylic polyurethane primer and TS96 -71 fluorocarbon polyurethane finish p rovides better corrosion protection [1]. Anaerobic microorganisms like Pseudodesulfovibrio indicus disrupted the passivation film of aluminium by forming sulfides, and the mixed biological contamination led to deterioration of fuel quality. In the co-cultivation system of Desulfovibrio bizertensis (SRB) and Methanosarcine barkeri (MPA), which exhibited the most severe corrosiveness, the potential microbial extracellular electron transfer mechanism accelerated the dissolution of aluminium alloy. There was no coupling relationship between the interspecies promotion of SRB in corrosion effects and the interspecies inhibition of fuel degradation by MPA. The degree of degradation of the sealant by SRB and MPA decreased over time, which was related to the fuel co - metabolism activity of microorganisms attached to the sealant surface. In the qualitative and quantitative models describing the corrosion of aluminium alloy and the degradation of sealant in fuel -water systems, we identified the galvanic electrochemical effect and the redox activity of fuel as two important parameters that might characterize the mechanism of seal failure in fuel tanks.

Objective Sulfate reducing bacteria (SRB) is an important corrosion factor in shale gas gathering and transportation pipeline systems, posing a threat to the safe operation of pipelines. Process and Methods In order to study the influence of carbon source on the corrosion behavior of SRB, a full immersion corrosion experience was conducted. The corrosion behavior of SRB was studied through methods such as planktonic bacterial content testing, corrosion weight loss testing, scanning electron microscopy observation, and electrochemical testing. Under the condition of a sodium lactate content of 350 mg/L, the maximum corrosion rate was 0.077 mm/a; Under the condition of a sodium lactate content of 500-3500 mg/L, the corrosion rate gradually decreased to 0.022 mm/a. Conclusion The results indicate that the reduction of carbon sources leads to bacterial starvation, which directly obtains electrons from metals and exacerbates corrosion. Under low-carbon source conditions, the content of planktonic bacteria is relatively low, but the corrosion rate and pitting depth may be large. It is not appropriate to use the content of planktonic bacteria to determine the strength of bacterial corrosion.

There are numerous oil reservoirs exhibiting low permeability. The strategic injection of carbon dioxide (CO 2) into these reservoirs has been identified as a promising approach to enhance the extraction efficiency of low-permeability oil fields [1]. However, those operations are often compromised by the corrosion failure of pipeline steel, which can have adverse effect on the overall exploitation process. The CO 2 can be used as a carbon source for microorganisms i n underground pipelines for chemoautotrophic metabolism and induce microbiological induced corrosion (MIC). As a typical corrosion microorganism, sulfate reducing bacteria (SRB) is capable of directly causing E -MIC and accelerate iron corrosion via chemical attack of its corrosive metabolites [2]. Some studies showed that the E -MIC may cause more severe corrosion than M -MIC. This work focus on whether the injection of CO 2 will have an impact on this corrosion process of MIC. In this present study, the corrosion behavior of X70 pipeline steel induced by Desulfovibrio Bizertensis SY-1 was studied via electrochemical measurements and weightloss experiments. The bacterial culture experiment found that CO2 had little effect on the cell number and attachment ability of SRB bacteria. The weightloss experiments results showed that corrosion of pipeline steel is more severe in the CO2 system and the proportion of E-MIC in corrosion in CO2 systems is significantly increased. Surface investigations revealed that corrosion products in CO2 systems are denser and pitting pits are generally deeper. Cytochrome c level tests shows that the Cyt C level in SRB increased by about 20% in CO2 system. The result of electrochemical measurements is consistent with the above conclusion, which suggests that CO2 promotes the secretion of Cyt C in SRB cells, thereby promoting their direct corrosion.

Conductive magnetic nanoparticles can affect the corrosion process of microbial influenced corrosion (MIC). In this work, the effects of different size Fe 3O4 nanoparticles (NPs) on the MIC process of Q235 carbon steel by Desulfovibrio vulgaris Hildenborough (DvH) are investigated.Surface examination, electrochemical testing, and starving studies demonstrated that Fe 3O4 nanoparticles influence microbial adhesion and accelerate corrosion. Interestingly, The impact of 100 nm nanoparticles on corrosion was the most noticeable, followed by 10 nm nanoparticles. Starvation experiments indicated a lower consumption amount of sulfate ions caused by DvH in the presence of 10 nm nanoparticles, further supporting the reduced MIC promotion effect compared to 100 nm nanoparticles treatment.Mechanistic research showed that 10 nm Fe 3O4 NPs cause DvH to produce more reactive oxygen species (ROS) than 100 nm nanoparticles. ROS can penetrate cells, di srupting the cell membrane's electronegative property and interfering with bacterial metabolism and gene expression, ultimately leading to bacterial death. This study offers new insights into strategies for controlling MIC.

There was a great evolution in the studies of microbial corrosion for more than twenty years. The scientific community took about 30 years from the beginning of the last Century to reach the first rigorous (electrochemical) explanation of why some bacteria induce fast steel corrosion. Hence, a half-century more was spent to reach a general agreement on the effect of biofilm in changing the electrochemical condition of metal surfaces, and electrochemical sensors to monitor biofilm were developed (it occurred in 80’ -90’ years particula rly) [1]. Investigations of electroactive biofilm later diffused worldwide, in-field and in labs. Those studies permitted sharing the amazing discovery that living organisms “electrically” (electrochemically) communicate with conductive, wet surfaces similary all over the world [2]. Next Generation Sequencing (NGS) tools, nowadays, allowed for documenting the rich pool of uncultivable bacteria and archaea populating the biofilm of in -field MIC cases [3]. Nonetheless, a clear correlation between the presence of specific groups (such as species, orders, genera) and corrosion risk in industrial settings was rarely convincingly demonstrated. This was mainly because the same organisms were also found in scenarios without corrosion and different microorganisms were most often found in other corroded scenarios. Based on the assumptions that a complex pool of microorganisms, rather than single components of it, can represent dangerous, uncontrollable, condition for MIC, the microbial pool sequenced on five different materials (pure copper, brass, pure iron, carbon steel and stainless steel) treated for fifteen days in the same inoculum (enriched idrogenothrofic archaea and bacteria) are here compared. Results shows a significant statistical difference correlated to the the microbial pool and the materials. This difference reflected a different corrosion behaviour of each analyzed material detected by impedance spectroscopy analyses.

Evaluation of the effect of sulphate-reducing bacteria (SRB) on the corrosion of mild simulated concrete solution at pH 9.35 and reinforced concrete (RC) using sulphoaluminate cement was carried out. Mitigation measure was done using organic silicon quaternary ammonium salt (OSA). For mild alkaline simulated concrete pore solution at pH 9.35, four systems were used: Blank (STR), STR + OSA (Blank with OSA), With SRB only (STR + SRB) and With SRB and OSA (STR + SRB + OSA). For the sulphoaluminate cement, three different systems were employed for this study: RC with sterilized NaCl (CS), RC with sterilized NaCl and SRB (CS-1), and RC with sterilized NaCl, SRB and OSA (CS-2). The 28-days SRB growth showed optimized number of sessile cells in the early immersion periods but reduced with extending the time. Consequently, the sessile cells induced the breakdown of the passive film through metabolic reactions of SRB. The corrosion resistance reflected by surface morphologies and electrochemical analysis showed that corrosion rate was higher in media containing SRB compared to media without SRB. The proposed mitigation mechanism shows that the silicate component of the OSA prevent the formation of biofilm while the ammonium component reduces the metabolic activities of SRB.

The offshore submarine pipeline usually adopts the coating combined with sacrificial anode cathodic protection(CP) system to prevent external corrosion from sea water and mud. Compared with the offshore pipelines in clear deep-water environment, the nearshore pipeline usually has a weight concrete layer and is laid in the sea mud, and the urrounding seawater is turbid, which makes the measurement of CP potential difficult and the effectiveness of CP hard to grasp. For this reason, a portable testin g tool developed to mearure CP potentials at the sacrificial anodes exposed to seawater and at both ends of the insulated joints of a nearshore pipeline. Samples of an in - service sacrificial anode and its electrochemical performance, and cathodic polarization behavior of pipeline material with weighted concrete were also tested. Combined with numerical simulation methods, calculations of CP potential distribution and sacrificial anode output current were carried out. Those results were used together for the effectiveness evaluation of CP of nearshore pipelines. The results show that the CP potential of the nearshore submarine pipeline under investigation is within the effective protection potential range, indicating that the CP is effective. This result has also been verified by the internal inspection data of the nearshore submarine pipeline. However, the test results show that the unevenness of sacrificial anode corrosion and the impact of stray current interference may lead to a shortened lifespan of the sacrificial anodes, which requires attention.

The leakage of DC stray current during subway operation causes serious electrical interference and corrosion to buried pipelines. With the continuous construction of subway lines, common long -distance oil and gas pipelines in urban areas are subjected to complex, high degree, and wide range DC stray current interference due to thei r proximity, intersection, or parallel with multiple subway lines.This article focuses on a typical interference section of a buried natural gas pipeline that is close to and intersects with multiple subway lines, causing severe corrosion. The continuous a nd synchronous monitoring of the ground potential or ground potential gradient of each subway track and the ground potential of the entire pipeline is carried out. Drawing on the basic concept of "beta curve" in NACE SP0169- 2013 and CP Interference, the "quasi beta curve method" is proposed to analyze and obtain the interference range and degree of stray current of the pipeline by each subway line in the interference environment of multiple subways.

As a novel green anti -corrosion technology, photoelectrochemical cathodic protection has gradually become an important approach for metal corrosion prevention. Nevertheless, conven tional titanium dioxide -based photoanodes are inefficient and unable to offer continuous protection in the dark. Silicon possesses excellent light absorption characteristics. By constructing a p-n heterojunction composite photoanode, the photoelectric conv ersion efficiency can be enhanced, yet it remains difficult to achieve continuous protection without light. In this study, we propose to combine n - type silicon nanowire arrays (SiNWs) with high specific surface area and organic semiconductor PEDOT:PSS to construct a new type of photoanode, and then combine it with copper -sulfur compounds (Cu2 -xS) to improve photoelectric performance and anti-corrosion capability. It is found that the current density of PEDOT:PSS/SiNWs photoanodes is significantly increased under visible light, which leads to the open circuit potential decrease much lower than that of corrosion potential for the metal. Especially the photoanode can still provide continuous protection after light off for more than several hours. The introduction of Cu2-xS further enhances light absorption and electron transport, thereby improving cathodic protection.

The development and utilization of marine resources are fundamentally dependent on various types of st eel. High -strength steel not only demonstrates exceptional strength but also exhibits a relatively low weight, thereby playing an increasingly pivotal role in the exploitation and utilization of resources within deep-sea environments [1 -2]. The corrosive n ature of seawater is notably high. When high - strength steel is utilized in seawater conditions, cathodic protection is typically essential for mitigating corrosion. However, the enhancement of high -strength steel's strength correlates with an increased sus ceptibility to hydrogen embrittlement [3 -4]. Particularly, when severe overprotection occurs during cathodic protection, it can lead to hydrogen embrittlement in the material [5 -7], presenting a significant risk to the service safety of marine structures. Therefore, investigating the cathodic protection parameters for high -strength steel in marine environments holds considerable importance for preventing both corrosion and hydrogen embrittlement failures [9-10]. In this study, the corrosion protection efficacy of three types of shipboard high-strength steel was evaluated through weight loss corrosion rate testing at various cathodic polarization potentials, while the sensitivity to hydrogen embrittlement of these steels was assessed using slow strain rate te nsile testing (SSRT). The minimum and maximum protection potentials for each type of high -strength steel were established based on their respective protective efficacy and hydrogen embrittlement coefficients. The findings indicate that the cathodic protect ion potential range for 600 MPa -grade steel is -761 mV to -1029 mV(vs.SCE), for 800 MPa -grade steel is -795 mV to -946 mV, and for 1000 MPa-grade steel is -762 mV to -907 mV.

In the impressed current cathodic pretection system for reinforced concrete in marine environments, the traditional insulating materials used are cementitous spacers or plastic spacers. Cementitous spacers have shown good application effects in various marine bridges and pile caps of wharfs that I have been involved in completing and operating. However, due to their brittle nature, they are prone to breakage during the concrete pouring process, leading to short circuits that require extensive repairs. This poses safety risks and inconveniences during construction. More seriously, certain areas cannot use cathodic protection technology because workers can not access to repair the damaged cementitous spacer, such as the steel bars at the bottom of pile caps of marine bridge. Therefore, for the design of the cathodic prevention system at Sanjiangkou Cross-Sea Bridge's pile caps, I employed PE insulation mesh ribbon as an alternative insulating layer and conducted verification tests. PE insulation mesh ribbon possess high strength and excellent toughness while remaining undamaged during construction activities, ensuring effective insulation after installation. Furthermore, their mesh characteristics do not impede concrete inflow or compactness during pouring processes. Field tests confirm that PE insulation mesh ribbon do not hinder uniform distribution of protective currents nor affect normal polarization behavior of steel bars while maintaining proper insulation levels. Polarization and depolarization tests on steel bars demonstrate potential shifts/decays exceeding 50mV within a very shor t time period close to 100mV of potential shifts/decays standards. These test results validate successful implementation of PE insulation mesh ribbons which address issues related to inaccessible areas requiring cathodic protection measures. The testing p rocedures and data are described and demonstrated comprehensively within this paper.

The composite anode of mixed metal oxide (MMO) coated on titanium substrate has been widely used in the impressed current cathodic protection against corrosion, electro -chlorination of seawater for bio -fouling control and some other electrochemical industries. Stability and electrochemical activity are very important properties of MMO anode, and need to be improved for application in some harsh conditions. This paper deals with the performance enhancement of MMO anodes modified by depositing interlayer of tantalum between the active oxide coating and the titanium substrate. TaOx interlayer was prepared by thermal decomposition in inert atmosphere. The results showed that the TaOx interlayer was amorphous consisting of multivalent Ta oxides. The electrocatalytic activity for oxygen evolution reaction and the stability of the composite anodes were improved obviously with adding the TaOx interlayer of appropriate th ickness, which can be attributed to the increase of electrochemically active sites and the extra protection for Ti substrate by the non - stoichiometric TaOx interlayer. Additionally, we have developed a composite anode of Ti/Ta -Ti/IrO2-Ta2O5 with a Ta-Ti alloy interlayer deposited on Ti substrate by dual glow plasma surface alloying. The investigation indicates that the electrode with Ta -Ti alloy interlayer reduces the agglomerates of precipitated IrO 2 nanoparticles and refines the grain size of IrO 2, thereby increasing the number of active sites and enhancing the electrocatalytic activity. The significant improvement in electrochemical stability is attributed to the Ta-Ti interlayer, which offers high corrosion resistance and effective protection for the titanium substrate.

Corrosion is the main factor that causes failures of gathering pipelines. Tens of corrosions exist in gathering pipelines. Idenfication of each corrosion failure is crucial important for corrosion control of gathering pipelines in oil & gas field. Corrosion failure analysis in oil & gas field is mainly relied on manual experience judgment, with low identification accuracy. In most cases, it only can be categoried into internal or external corrosion. Even thouth some corrosion failure pipes are sen t to laboratories for analysis, the whole process is complex, inefficient and high cost. In this work, the corrosion failure database of gathering pipelines in oil and gas field is established, with more than 25000 corrosion failure cases. Machine learni ng is adopted to establish an intelligent recognition model of corrosion failure based 831 typical corrosion failure cases, which is selected from corrosion failure database. The results show that image classification technology based on deep learning can be used for corrosion failure analysis of oil & gas pipelines. Unimodal model, such as vision transformer(ViT), can be used for classification of corrosion into internal or external corrosion, as well as corrosion with obvious characteristics, such as CO 2 corrosion, SRB corrosion, erosion corrosion, and dissolved oxygen corrosion. A multimodal model is required for indentification of external corrosion of internal corrosion with less obvious features.

To clarify the long -term service stability of reference electrodes for CP monitoring and the corrosion behavior of buried pipelines in saline -alkali soil environments, this paper deeply investiga tes the real-time evolution of free corrosion potential, versus six different types of reference electrodes, of pipeline steel specimens through long-term exposure tests in saline-alkali soil collected from the field, and also studies the corrosion behavi or of specimens after the exposure. The test procedures are proven efficient and desirable for selecting long-term reference electrodes suitable for purposes of CP and corrosion monitoring and assessment in saline -alkali soils, and further, of field data validation. Meanwhile, the corrosion rate of specimens are recorded with exposure time, and the correlation of the corrosion rate tendency with soil characteristics is also studied. The test results indicate d that gel type copper sulfate reference electrode s were more suitable for saline -alkali soil environments than other candidates, and the corrosion rate of specimens in saline -alkali soils was significantly higher than that in ordinary soils. The results provide a solid theoretical basis and practical gui dance for the corrosion protection management of pipelines in saline -alkali soil environments.

The influence of astronomical tide changes on the operation of rectifier - controlled impressed current cathodic protection system for metal facilities in a domestic nuclear power plant's seawater environment is analyzed. It is pointed out that under hydrological conditions with significant tidal variations, potentiostat equipment should be used for impressed current cathodic protection system control. On this basis, the impressed current cathodic protection system of the nuclear power plant was comprehensively modified, achieving automatic and intelligent control of the system, and ensuring the ON potentials of underwater metal facilities within the design range, effectively protecting them.

Lake Albert is a freshwater lake on the border of Uganda that has low electrical resistivity but is home to microorganisms and dissolved oxygen. Through the analysis of two cathodic protection designs of sacrificial anode and impressed current of steel structure platform in lake water, the results show that the sacrificial anode is large in number, difficult to install and poor in economy, and the impressed current method has great advantages. However, in view of the excellent maintenance -free performance of the sacrificial anode in the early operation stage, some owners still hope to use the sacrificial anode protection mode, so the cathodic protection design of the steel structure in the lake water is analyzed and summarized from three aspects: The determination of cathodic protection current density, the design and installation of sacrificial anode skid and the installation and fixing of impressed current. That means three directions of cathodic protection design of freshwater steel structure has been pointed out.

This paper carries out a detailed investigation and analysis of the current status of regional cathodic protection systems in different flight areas, aiming at exploring the key factors affecting the effectiveness of regional ca thodic protection in flight areas. Through on-site testing and data collection of cathodic protection systems in different flight zones, the operation status and problems of cathodic protection systems are analyzed, and through comparative analysis, it is found that the existing cathodic protection systems in certain flight zones have certain deficiencies in the protection scope and effect, especially the phenomenon of uneven potentials in certain areas; through the analysis, it is found that the key factor s affecting the effect of regional cathodic protection in flight zones are flight Through analysis, it is found that the key factors affecting the cathodic protection effect in the flight area are the large number of grounding reinforcement nets of electri c valve wells in the flight area and the grounding of structures in the apron area. Based on the test results, the method of determining the cathodic protection current for different types of flight areas is given, which provides data support and theoretic al guidance for the design of cathodic protection systems in similar flight areas.

In recent years, due to the large-scale construction of wind power and shore power projects, the laying of underwater high -voltage alternating current (AC) ca bles has been increasing annually, often running parallel to nearby underwater pipelines and forming a " common corridor." This arrangement generates alternating current induced voltage and current on the pipelines, putting them at risk of AC interference. While substantial research has been conducted on AC interference patterns for onshore oil and gas pipelines, there is a lack of systematic study and understanding regarding AC interference issues for underwater pipelines. How to understand the AC interference law of high-voltage AC cables to submarine pipelines and determine the safe distance has become an urgent demand in practical production. Based on this, this paper establishes a calculation model for AC interference on underwater pipelines caused by h igh-voltage AC cables using CDGES software. Through simulation calculation, the influence law of many factors such as parallel distance between AC cables and pipelines, parallel length, cable load current, anticorrosive coating resistivity and longitudinal pipeline resistance per unit length on AC interference parameters of pipelines was investigated. Based on the principles of electromagnetic induction and AC circuits, the safe distances avoiding AC corrosion under different parallel lengths and load currents were discussed, which can provide a reference for the evaluation of AC interference of submarine pipelines and the selection of submarine routing.

The on-site inspection and buried coupon experiments were conducted on two long -distance pipelines running parallel to high -voltage transmission lines. The investigation revealed that pipeline 1 has a parallel distance to the transmission line of less than 400 meters, with a parallel length of approximately 17.5 kilometers, while pipeline 2 has a parallel distance of less than 100 meters, with a parallel length of about 3 kilometers. Five locations of the two pipelines were selected to buried corrosion coupons, and the AC and DC parameters of the pipelines were monitored continuously for 24 hours. After three months, the corrosion morphology, corrosion products and corrosion rate of the specimens were obtained. The correlation between AC interference parameters, cathodic protection parameters, and corrosion behavior was futher analyzed. The results indicate that the polarization coupons at test points 1# and 2# showed the alternating current density of above 200 A/m2 and a corrosion rate higher than 0.1 mm/y, whereas the polarization coupons at test points 3#, 4#, and 5# exhibited a relatively low corrosion rate of about 0.03 mm/y. Macroscopic observations of the corrosion morphology indicated that the coupons experienced uniform corrosion.

In view of the applicability of ultrasonic guided wave technology on low - pressure gas pipelines, test experiments were carried out on typical indoor unburied failed pipe sections, outdoor buried pipe sections and a ctual field service pipelines. The effects of different soil compaction, different defects, different pipe diameters, different pipe section lengths, welds, elbows, tees and pipeline deformation on the detection effect of ultrasonic guided wave technology were explored, and the influence of different factors on ultrasonic guided wave technology detection was clarified. The experimental study of typical indoor unburied failed pipe sections found that soil compaction, pipeline defects, welds, elbows, tees and pipeline deformation would cause different degrees of attenuation of ultrasonic guided wave detection signals. The experimental study of outdoor buried pipe sections found that with the decrease of soil resistivity, the effective detection distance of ult rasonic guided wave technology showed an overall decreasing trend. The field test of the actual service pipeline excavation found that the test results of ultrasonic guided wave technology were basically consistent with the actual excavation corrosion resu lts, and the effective detection distance on the actual service pipeline was about 15m~30m. This conclusion has important practical guiding significance for the application of ultrasonic guided wave technology in the actual service low-pressure gas pipeline.

As the use of directional drilling to lay pi pelines in the oil and gas industry becomes more widespread, there is an urgent need to effectively evaluate the cathodic protection level of the pipelines during directional drilling operations. This article takes the example of a horizontal directional drilling crossing section and a pipe gallery with connected protection for underground pipelines, by collecting and testing the basic information of the pipeline and establishing numerical simulation models, designing the device for evaluating the polarizat ion characteristics of the drilled pipeline, when the pipe burial depth is 1m, there is an oxygen diffusion limit zone in the polarization curve, when the pipe burial depth is more than 5m, the soil oxygen content is very low, the sample polarization curve is the oxygen diffusion limit zone, the polarization characteristics of the sample change as the pipe burial depth increases, the cathodic protection boundary conditions of different burial depths are determined. Through numerical simulation calculation a nd analysis of the cross -sectional linked protection effect and influencing factors, the law of the effect of different forms of sacrificial anode bed position and number on the cross-sectional protection effect is obtained. This study provides a reference for future cathodic protection design.

During the back -pulling proce ss of horizontal directional drilling (HDD) pipelines, the coating inevitably experiences some degree of damage, compromising the pipeline's overall safety. To address this, cathodic protection is typically employed to provide additional protection to the damaged areas of the coating. However, assessing the effectiveness of cathodic protection in HDD pipelines presents significant technical challenges, particularly in accurately determining the polarization characteristics at varying burial depths. This study developed a deep-well polarization testing device and conducted field tests on a real -world oil pipeline. The results indicated that at a burial depth of 1 m, the pipeline showed an oxygen diffusion limitation zone. In contrast, at depths greater than 5 m, the soil’s oxygen content was extremely low, and no oxygen diffusion limitation zone appeared in the polarization curves. As the burial depth increased, the pipeline's polarization characteristics underwent substantial changes. This device offers a rel iable method for measuring cathodic protection potentials at different depths in HDD pipelines, providing a scientific foundation for establishing cathodic protection evaluation standards and optimizing design parameters.

In recent years, aluminum -based sacrific ial anodes have been widely used in many service environments because of their negative driving potential, large capacitance, good anodic activation solubility and long service life.However, in some harsh environmental conditions, such as high temperature oil sewage, oil and gas well environment, the traditional sacrificial anode in high temperature, high salinity, highly corrosive media, the use of poor, anode surface will appear serious pits, low dissolution activity, current efficiency decline, so that t he oil well pipeline can not be effectively protected.Therefore, it is necessary to further improve its overall performance in this harsh environment. In this paper, Al-Zn-In anode alloy is used as the primary tercomponent, and then the composition design is optimized through alloying and heat treatment. In terms of experiment, GB/T17848-1999 sacrificed-anode constant current experiment is carried out to test the open circuit potential, working potential, capacitance and current efficiency.At the same time, electrochemical tests such as polarization curve, electrochemical impedance spectroscopy, scanning Kelvin probe SKP (micro -region potential distribution measurement), metallographic structure observation and analysis were carried out for anode materials i n high -temperature oil well produced liquid. Furthermore, virtual crystal approximation (VCA) was used to quantitatively design anode substrate composition. By calculating the anode work function and the adsorption energy of the main molecules and ions of the oil well produced liquid on the surface of the anode alloy, the interfacial affinity between the alloy composition and the oil well produced liquid is predicted: the greater the affinity, the greater the tendency of dissolution reaction between the alloy interface and the produced liquid solution, and the better anode dissolution activity is expected. After optimization design, several new sacrificial anode samples were prepared, and comprehensive electrochemical protection performance tests were conduc ted. Two sacrificial anode components were selected to meet the requirements of high - temperature and highly corrosive oil well environments.

In this study, n-type silicon nanowire arrays (SiNWs) are used to replace the traditional TiO 2, and PEDOT:PSS is composited with the photoanode SiNWs to construct a new type of composite photoanode based on PEDOT:PSS thin film/silicon nanowire arrays, and simulate the marine environment to establish a phot ogenerated cathodic protection system for the photoanodes and the metal electronic materials in the shipborne electronic equipment. The above composite photoanode's good light absorption performance, stability and electron transfer performance are utilized to improve the protection ability of the photoanode on 304 stainless steel, and the optical performance, electrochemical performance and cathodic protection mechanism of the composite photoanode are investigated. Especially in the dark state, the electron s stored in PEDOT:PSS can provide continuous cathodic protection for metal materials, realizing long-term and stable metal corrosion protection.

In obtaining a thorough knowledge of basic technical principles for cathodic protection, determination of optimum engineering solutions as well as selection of applicable, optimum overall performance of materials and ancillary products should be made in accordance with the a ctual projects. Relevant domestic and overseas standards and specifications provide only guiding recommendations, some of which are inadequate and deficient, misleading the development and application of the cathodic protection and resulting in unnecessary economic loss.

在全面了解阴极保护基础技术原理上,依据工程实际情况,确定最佳技术方案 措施,选择适用、综合性能好的材料及配套产品。国内外相关标准、规范只是指导性 建议,其中部分内容存在不足和缺陷,误导阴极保护技术的发展和应用,造成了不必 要的经济损失。

Since the properties of oxide films are crucial for designing new corrosion and oxidation-resistant alloys, numerous studies have focused on their enhanced characterization. Among the various techniques available, electrochemical impedance spectroscopy (EIS) is commonly used to obtain in-situ physical information about passive layers. For passive materials, the electrochemical impedance response often deviates from ideal capacitive behavior due to resistivity distribution within the oxide layer. This distribut ion follows either a power law (as proposed in Power Law Model (PLM)) [1] or an exponential law based on the Young model [2]. Surface analysis has shown that passive films grown on stainless steels may consist of two distinct layers with different properti es and compositions. Therefore, models used to analyze the electrochemical impedance response must consider this duplex structure. In the present work, two models were applied: the PLM, which assumes a homogeneous oxide film with a power -law distribution o f resistivity, and the recently proposed Dielectric Bi-Layer Model (DBLM), which accounts for an inner layer with a constant resistivity (ρ 0) resulting in an impedance resembling a pure capacitance in parallel with a resistance, and an outer layer with an exponential resistivity distribution according to Young's theory [3]. In the presented work, passive films grown on 316L stainless steel with different physicochemical conditions (applied potentials, solution chemistry, temperature...) were tested. Resistivity profiles and regressed physical parameters were discussed concerning oxide thickness. X -ray photoelectron spectroscopy further described the oxide film's nature and structure. The applicability of the hypotheses in the DBLM could be then discussed regarding the passive film features.

With the developing technolo gy for the disposal of High Level Nuclear Wastes (HLNWs), copper alloy has been selected as the canister material. However, the regarding corrosion issue of copper canister in crystalline rock repository remains unclear, so that a significant question arises as to the suitability of copper alloy toward the intended purpose. Whether Oxygen-free, Phosphorous-doped copper (OFP-Cu) is passive in sulfide -containing geochemical brine and what corrosion mechanism it obeys need to be ascertained. By means of DC p olarization and electrochemical impedance spectroscopic (EIS) techniques, the corrosion behavior and corrosion mechanism of oxygen free phosphorus copper in simulated geological brine for HLNWs was investigated. The Point Defect Model was successfully developed to study the passivation of copper alloy. Copper cation vacancy is identified as the preponderant point defect within the passive layer by Point Defect Model coupled EIS optimization (PEO) and Mott -Schottky analysis. Corrosion kinetic parameters for the generation/annihilation of ionic defects were accounted by PEO. Sulfate is found to induce the passivity breakdown by promoting the ejection of copper cation vacancies, resulting in a larger passive dissolution current density and a decrease thickness of barrier layer.

With the global expansion of pressurized water reactors (PWRs), addressing corrosion damage, particularly stress corrosion cracking (SCC), of critical materials has become paramount. This study investigates corrosion phenomena in PWRs through three key areas: in -situ analysis, diagnostic theory, and mechanistic modeling. A multifunctional research platform capable of operating under extreme super/subcritical water conditions at temperatures up to 500° C was developed. This platform was used in -situ electrochemical tests to simulate the corrosion behavior of primary circuit materials in PWRs. Results show that with increasing temperature, the open-circuit potential of nickel -based alloys decreased, current density significantly increased, and impedance modulus declined. All tested alloys exhibited n -type semiconductor properties in their passive films. Additionally, the impedance initially increased and then decreased as dissolved hydrogen levels rose, suggesting that trace hydrogen improves corrosion resistance. The Point Defect Model III (PDM III) was employed to analyze these behaviors further, providing insights into the kinetics of corrosion at the microstructural level. Notably, PDM III was refined by incorporating cathodic reaction descriptions and optimizing methods for evaluating passive film capacitance and electronic impedance. This enhanced diagnostic framework was applied to corrosion processes in supercritical water environments. Finally, the coupled environmental fracturing model was utilized to assess operational conditions, demonstrating that optimizing dissolved hydrogen concentration and pH levels can effectively slow crack growth, thereby extending equipment service life. This work enhances our understanding of the corrosion mechanisms affecting nuclear materials and offers tools and models to improve material selection, design, and corrosion mitigation in nuclear power plants.

The application of bipolar electrochemistry results in a potential gra dient acting along the working electrode surface, which in turn yields the full spectrum of anodic -to-cathodic polarisation responses. Bipolar electrochemistry can be used to study different types of corrosion, from crevice corrosion, pitting corroissn, general corrosion, passivation area, and cathodic response can be obtained on one BPE sample in a single experiment. However, one of the limitations of bipolar electrochemistry for corrosion screening is that corrosion behaviour at higher (or lower) applied potentials cannot be observed. The bipolar electrochemistry set -up was therefore modified to investigate the effect of a superimposed applied potential, and the effect of asymmetrically acting potential gradients on the working electrode. These novel bipolar electro-chemistry set -up designs enable the assessment of a number of corrosion processes to be investigated.

both high performance and durability. These steels exhibit excellent mechanical properties, making them suitable for harsh environments such as offshore platforms, downhole equipment, and high-pressure vessels [1-3]. However, these environments present a significant risk of microbiologically influenced corrosion (MIC), which is primarily driven by sulfate -reducing bacteria (SRB) [4-7]. This form of corrosion is a growing concern in the oil field, as SRB have a remarkable ability to colonize metal surfaces, accelerating localized corrosion rates and compromising the structural integrity of critical components. Addressing MIC in ultrahigh-strength stainless steels, therefore, becomes paramount for improving the safety and longevity of these systems. While conventional stainless steels such as 316L, 2205 duplex, 321 SS, and 304 SS have been developed with superior corrosion resistance, they remain vulnerable to SRB-induced MIC. The ability of SRB to thrive in anaerobic conditions, metabolize sulfates into sulfides, and trigger severe pitting corrosion highlights the limitations of current corrosion mitigation approaches. Recent research has focused on augmenting 3 Corresponding authors: mengchao.niu@polyu.edu.hk, tqwu@xtu.edu.cn stainless steels with antibacterial properties as a novel strategy to counter MIC. One promising approach involves the incorporation of copper (Cu) into stainless steel alloys. Copper is well known for its str ong antimicrobial activity, which is effective against a wide spectrum of bacteria, including those responsible for MIC and biofilm formation. Cu-bearing stainless steels have shown considerable promise in reducing bacterial colonization and biofilm format ion, thereby offering an additional line of defense against microbial corrosion [8, 9]. However, Cu alloying could introduce complexities in corrosion resistance, such as promoting pitting corrosion in environments where chloride ions are present [10]. The overall impact of Cu on corrosion behavior depends on the specific alloy composition, the environmental conditions, and the interaction between Cu and other alloying elements like Cr and Ni. In ultrahigh-strength materials like maraging steels, the main challenge lies in balancing the mechanical properties and corrosion resistance. The atomic -scale mechanisms of Cu’s effect on both mechanical and corrosion properties are still under investigation. In this study, we explored the potential of Cu alloying in ultrahigh -strength Fe-Ni-Co-Cr-Ti maraging stainless steels. These maraging steels are notable for their exceptional mechanical properties, with tensile strengths excee ding 1.8 GPa due to the high-density precipitation of (Ni,Ti) -rich nano-precipitates during aging treatment. By introducing Cu into the maraging stainless steel, we aimed to enhance not only its mechanical properties but also its antibacterial performance and corrosion resistance in SRB environments. Our investigation revealed that Cu addition improves both the strength and the corrosion resistance of the maraging stainless steel. The presence of Cu significantly enhanced the stability of the passive oxide layer on the steel surface, which plays a critical role in pitting corrosion resistance. Cu ions (Cu2+), released from the steel, disrupt bacterial cell membranes and interfere with essential cellular processes, effectively reducing SRB colonization and bi ofilm formation. This antibacterial mechanism, coupled with improved corrosion resistance, suggests that Cu-bearing maraging stainless steels could be highly effective in MIC -prone environments. To comprehensively understand the role of Cu in these improve ments, we employed advanced characterization techniques. Using 3D atom probe tomography (3D-APT), we studied the element segregation and nanoscale precipitation behavior of the alloy. High -resolution transmission electron microscopy (HR -TEM) provided insights into the microstructural evolution of the steel during aging, while X -ray photoelectron spectroscopy (XPS) enabled us to analyze the surface chemistry and the composition of the passive oxide layer. Our results showed that the co-precipitation of Cu wi th Ni 3Ti nano -precipitates contribute to the alloy’s increased strength. Cu addition promoted a more uniform distribution of Cr and Mo, improving the corrosion resistance, reducing the likelihood of pitting corrosion induced by SRB. In summary, the novel Fe -Ni-Co-Cr-Ti maraging stainless steel alloyed with Cu demonstrates a unique combination of ultrahigh strength, enhanced antibacterial properties, and superior resistance to MIC. This study bridges the gap between mechanical performance and corrosion resistance in maraging stainless steels, highlighting the atomistic mechanisms responsible for these enhanced properties. The findings pave the way for the development of next -generation materials for critical applications in the oil and gas industry, where microbia l corrosion poses a significant threat to structural integrity and operational safety. This research provides an atomic - scale understanding of how Cu influences the mechanical, antibacterial, and corrosion properties of maraging stainless steel. The insigh ts gained from this study can guide future alloy design and open up new avenues for combating MIC in demanding industrial environments.

Various factors affect atmospheric corrosion rate and uniformity, thus influencing material life-span and system reliability. In order to study the electrochemical characteristics of pure iron under the influence of dynamic saltwater droplets in different humidity environments, a two-dimensional axisymmetric model containing heat and moisture flow modules was developed. In contrast to previous models where the vertical flux of oxygen was solely determined by diffusion, the current model accounts for convection as a significant contributing factor, and the contribution of convection to oxygen transfer is shown in Fig.1(a). The findings suggest that under varied humidity conditions, the interior of the droplets manifests distinct convective structures and velocities so that the corrosion interface displays diverse electrochemical characteristics, Fig.1(b) shows the distribution characteristics of electrode potential at different humidity levels, indicating that the corrosion distribution characteristics commonly associated with the Evans ring are a special case occurring under high humidity conditions. The model also elucidates the role of humidity in local corrosion during the initial stages, its impact on the distribution characteristics of the cathode and anode (Fig.1(c)), and its effect on the distribution of oxygen within the droplets. Elevated conductivity in more porous corrosion products may lead to increased unevenness in corrosion, thus heightening the risk of localized corrosion (Fig.1(d). These conclusions are effectively corroborated through the measurement of local electrochemical impedance under different humidity conditions, employing a concentric electrode array. This study provides insights into the conditions under which localized corrosion is likely to occur; it facilitates the understanding and mitigation of corrosion risks in various applications.

The degradation of reinforced concrete structures remains a serious issue in infrastructural systems, such as buildings, highways, and bridges. The problem is caused by the presence of chloride, either from being present in the concrete mix (e.g., from the use of brackish water or the addition of CaCl 2 as a “setting agent”) or by ingress from the external environment (e.g., road salt or marine environments). A metric known as the chloride threshold (CT) has been developed to describe the susceptibility of the steel to chloride -induced passivity breakdown. Despite the widespread use of CT as a metric for describing the impact of chloride on rebar corrosion, a theoretical basis for this metric does not appear to have been established. In addition, the CT is a highly distributed parameter, reflecting the practical difficulty in controlling or measuring various environmental parameters in concrete and in reliably detecting passivity breakdown. Therefore, we have conducted several tasks to theoretically and practically understand how rebar corrosion is dependent on CT. We have established a rich database of CT and its associated primary and secondary influencing factors. Statistical analyses reveal that CT is lognormally distributed whereas potential parameters are normally distributed. We also demonstrated that it is possible to calculate CT in pure, empirical manner using Artificial Intelligence (AI) techniques, in accordance with point defect theory prediction, through trained artificial neural network. However, a significant amount of work remains to be completed in the future in developing an understanding of steel corrosion in concrete. Our knowledge of underlying factors that control the CT is still very poor due to the paucity of accurate data in the literature, and it is ultimately insufficient to provide a more accurate estimate of CT than that obtained by either the ANN prediction or point defect theory analysis at this stage.

Coatings play a crucial role in safeguarding around 90% of materials against corrosion. However, surface defects are inevitable during the formation of the coating. While research on the corrosion failure behavior of organi c coatings has been extensive, study on the galvanic corrosion behavior between conductive coatings and metal substrates remains limited. In this study, graphite coatings were applied to the surface of 2024 aluminum alloy. The study aimed to examine the ga lvanic corrosion behavior between them, clarify the corrosion failure mechanism of the coating system, and analyze the transport process of corrosive media within the coating. The main conclusions are as follows: the average potential difference between th e 2024 aluminum alloy and the graphite coating was approximately 0.76 V/SCE, with a galvanic current density of 8.06× 10 -4 μ A/cm2. The corrosion failure process of the conductive coating system can be divided into three stages based on the characteristics of EIS. Correspondingly, the transport behavior of the corrosive medium (primarily water) within the coating also undergoes three stages. Initially, the conductive coating system exhibited two time constants. With the increasing of immersion time, the forma tion of a corrosion product film introduced a third time constant, indicating the arrival of chloride ions at the surface of the 2024 aluminum alloy. In the later stages, the conductive coating system reverted to two time constants, which is attributed to the disappearance of chloride ions leading to the absence of capacitive loop in the high frequency. Simultaneously, due to the blocking effect of the graphite laminating structure on the permeation of corrosive media, the Warburg impedance is always accompanied throughout the entire immersion period. 0 0.0 2 .0 x 1 0 4 .0 x 1 0 6 .0 x 1 0 8 .0 x 1 0 1 . 0 x 1 0 1 . 2 x 1 0 0.0 2.0x10 4.0x10 6.0x10 8.0x10 Z '/(Ω ·c m 2) -Z''/ (Ω ·cm 2) Time/d 0d 8d 16d 22d 23d 27d 31d 32d 40d 49d 0 10 -3 10 -2 10 -1 10 0 10 1 10 2 10 3 10 4 10 5 0.0 2.0x10 4.0x10 6.0x10 8.0x10 1.0x10 1.2x10 F r e q u e n c y /H z |Z| (Ω ·cm 2) Time/d 0d 8d 16d 22d 23d 27d 31d 32d 40d 49d 0 10 -3 10 -2 10 -1 10 0 10 1 10 2 10 3 10 4 10 5 F r e q u e n c y /H z Phase/° Time/d 0d 8d 16d 22d 23d 27d 31d 32d 40d 49d Fig.1 Evolution of Electrochemical Impedance Spectroscopy [1] SUN W, YANG Y, YANG Z, et al. Review on the corrosion-promotion activity of graphene and its inhibition [J]. Journal of Materials Science & Technology, 2021, 91: 278-306. [2]胡吉明, 张鉴清, 谢德明,等. 环氧树脂涂覆 LY12 铝合金在 NaCl 溶液中的阻抗模型 [J]. 物理化学学报, 2003, 46: 144-149.

The micro -zone interface of inclu sions with the steel matrix of X70 high - strength pipeline steel with Al-Ti deoxidization and Mg-Ca compound treatment in the tropical marine environment was investigated. Results revealed that the Volta potential difference increased in proportion to the r esidual stress at the interface of inclusions with the steel matrix. The early corrosion behavior of pipeline steel was investigated by immersion testing and corrosion morphology assessment. Three stages of the early corrosion process of pipeline steel wer e elucidated based on micro mechano - electrochemical (M -E) interaction. Thermodynamic and kinetic models of M-E interactions at the micro-scale were proposed.

Erosion-corrosion is the acceleration or increase in rate of deterioration or attack on a metal because of the relative movement between metal surface and a corro sive fluid [1]. Generally, this movement is quite rapid, and mechanical wear effects or abrasion are involved. Metal is removed from the surface as dissolved ions, or it forms solid corrosion products that are mechanically swept from the metal surface. Compared with corrosion of metallic materials in stagnant corrosive media, it is very serious and has a complex mechanism. Thus, many researchers have paid their attentions to erosion-corrosion since last century. Throughout the studies on erosion-corrosion, their history would be divided into four stages. Fundamentally, erosion corrosion is one type of flow -induced corrosion. The classification of flow-induced corrosion was made by E.Hetz [2].During this time, the effect of the turbulence of flow liquid on corrosion rates of metals in a flowing medium was firstly focused on and many attempts were made to develop the relationship of Reynolds Number(Re), Sherwood Number (Sh)and Schmidt number(Sc) with corrosion rates[3]. Nextly, with further studying the effect of hydrodynamic factor on erosion-corrosion, it was found that the higher mass transfer coefficient, the higher corrosion rates, and that there is a critical surface shear stress above which erosion corrosion rate increases abruptly [4]. Up to now, the critical velocity has been used to control erosion corrosion of pipes in corrosion control design. At the third stage, professor Postlethwaite started to use CFD software for studying the effect of the boundary parameters of flow liquids on erosion corrosion [5]. At the same time, there were many attempts to establish the relation of the boundary parameters of flow liquids with erosion-corrosion rates [6]. And that the synergistic effect between hydrodynamic factors and electrochemical factors attracted many attentions [7]. It was worth maintaining that the EIS was used to study the electrochemical process kinetics of a metal in a flowing corrosive fluid [8]. Finally, as said above, there few papers which focused on studying the impact of hydrodynamic factors on the surface layer of metals in a flowing medium. In this case, an attempt was started to investigate the mechanical degradation of the surface layer of metals induced by hydrodynamic factors and the synergistic effect between the mechanical degradation of the surface layer of metals and corrosion [9]. In the future, some attentions should be paid to study the accelerated mechanism of erosion corrosion at an atom scale using some software, including the predict erosion corrosion using machine study methods. Kew words:Erosion corrosion;flowing fluid;synergistic effect; hydrodynamic;electrochemical factors Refeences [1] M.G.Fontana. Corrosion engineering (third edition),New York:McGraw -Hill Book Company,1987. [2] E.Heitz. Chemo-mechanical effects of flow on corrosion. Corrosion,47(2)1991:135- 145. [3] U.Lotz Velociy effects in flow induced corrosion. Paper No.27, Corrosion 90, Bally’s Hotel, Las Vegas, Nevada,USA, Aprial 23-27,1990. [4] E.J.Wright, K.D.Efird, JA.Boros, T.G.Hailey. Rotating cylinder electrode (RCE) simulation of flow accelerated corrosion in sweet production. Proceeding 12th international corrosion congress,Houston Tx,Sept.19-24,1993. [5] Nesic.S.Postlethwaite J., The Canadian Journal of Chemical Engineering,69,1991,698-703. [6] YONG Xing-yue, ZHANG Ya-qin, LI Dong-liang, JI Jing, QU Yi-xin, WANG Ji-dong. Effect of Near-wall Hydrodynamic Parameters on Flow Induced Corrosion, Corrosion Sciences and protection Technology,23(3)2011:245-249. [7] M.M. Stack, N. Corlett, S. Zhou, A methodology for the construction of the erosion-corrosion map in aqueous environments, Wear 203–204 (1997) 474–488 [8] Yong Xingyue,Liu Jingjun, Lin Yuzhen, EIS of duplex stainless steel in flowing corrosive media.Journal of Chemical Industry and Engineering(China),54(12)2003:1713-1718. [9] Zhang Ru, Shen Hanjie, Zhang Yaqin, Li Dongliang, Li Yanjia, Yong Xingyue. Surfacelayer nano -mechanical responses to interaction between cavitation and electrochemical corrosion. ACTA METALLURGICA SINICA 49(5) 2013:614-620.

The interactions and synergies between the different components of high entropy alloy (HEA) can endow the material with special features. Therefore, HEA-boride cermet composite is prepared via an in-situ reaction for the first time. The microstructure evolution and corrosion resistance are investigated for sintering temperatures in the range of 1000–1300 °C. The phase structure contained Mo2FeB2, MoB2, and FCC. The hard phase of the composite was composed of Mo 2FeB2, MoB 2, whereas the bond ph ase comprised various types of alloys or intermetallic solid solutions. The highest percentage of the Mo2FeB2 phase was 48.9% at 1100 °C. The Mo 2FeB2 phase exhibited a preferential growth tendency along the {100} crystalline plane. As the sintering temperat ure increased, the preferential growth of Mo 2FeB2 in the {100} crystalline plane gradually increased. The composite sintered at 1100 °C exhibited the most favorable corrosion resistance as a result of the synergistic effect of the Mo2FeB2 corrosion-resistant phase, small grain size, low porosity, and low strain dislocation level. The OCP was -0.34 V, Ecorr was -0.52 V, and Icorr was 2.07× 10-6 A/cm2. As a crystal with a tetragonal structure, the densely arranged surface of Mo2FeB2 was a {111} crystal plane. Consequently, the {110} crystal plane, which was in close proximity to the {111} crystal plane, exhibited a lower surface energy and denser atomic arrangement, rendering it less susceptible to corrosion. Nevertheless, an elevated sintering temperature dimin ished the ability of Mo2FeB2 to grow along the {110} crystal plane, thereby accelerating the corrosion rate of the cermet. In addition, the high dislocation density could provide additional corrosion channels or active sites, facilitating the penetration and diffusion of corrosive media into the interior of the material. The lowest level of small-angle grain boundaries in cermet was observed at a sintering temperature of 1100 °C, resulting in a relatively low concentration of localised high energies and dislocations.

New generation Al-Cu-Li alloy has been increasingly used in aircraft structures due to its high specific strength, which could efficiently reduce the structure weight and thus improve fuel efficiency. However, its high corrosion susceptibility may endanger the safe operation of aircraft, which thus limits its wider application. PEO of aluminium has been extensively studied with the related industrial process available. Unfortunately. Little attention has been paid to the influence of the aluminium substrate on the micro-arc oxidation (MAO) behaviour, which may d ramatically affect the corrosion resistance of the resultant film. In the present work, the influences of coarse intermetallics, dispersoids and precipitates on the MAO behaviour of 2A97 alloy, a representative Al-Cu-Li alloy, have been systematically stud ied. It was revealed that coarse intermetallics may cause micron-sized voids that compromise the defectiveness of the MAO ceramic film whereas the precipitate mainly affects the MAO behaviour by affecting the Cu content of the substrate. Following the illu stration of the MAO behaviour, an ultrasound assistant MAO process was proposed, which successfully achieves a ceramic film with enhanced compactness and thus promotes the corrosion resistance of the substrate.

Flux residues and marine service conditions expose lead -free solder join ts to environments containing halide ions, which can induce corrosion and electrochemical migration[1,2]. The role of silver (Ag) in electrochemical migration within Ag-containing lead-free solders remains under investigation[3]. In this study, we synthesized an Ag- 60Sn alloy with approximately 20% Ag 3Sn content and examined the effects of high - temperature and high-humidity oxidation, as well as various halides, on the corrosion and electrochemical migration behaviors of Ag 3Sn and β -Sn. Following high - temperature and humidity exposure, selective oxidation of Ag3Sn led to the formation of pure Ag. Both before and after oxidation, β-Sn showed preferential corrosion in NaCl, NaBr, and Na 2SO4 solutions, with minimal corrosion of Ag 3Sn. Conversely, Ag 3Sn corroded in NaI solution prior to oxidation, whereas a fter oxidation, Ag corroded and β-Sn remained unaffected. In terms of electrochemical migration, Sn dendrites consistently formed in NaCl and NaBr solutions, irrespective of oxidation state, while Ag dendrites appeared in NaI environments after oxidation. No dendritic growth was observed in Na 2SO4 solutions. This study identified critical corrosion conditions for Ag3Sn and used X -ray Photoelectron Spectroscopy (XPS) to analyze dendrite composition. Based on these results, we developed an electrochemical mig ration model for Ag3Sn and β-Sn in halide media.

Layered double hydroxides (LDH) have many merits and have been widely used for corrosion protection of metals, including used as the conversion layers for a protective coating system. Vertically-grown morphology is favorable for a conversion layer, but LDH coating having such orientation can only be prepared by hydrothermal method, which is time consuming and requires high temperature. In this work, a novel two-step electrodeposition method was proposed to in-situ prepare vertically grown Zn-Al LDH coating on either galvanized steel, aluminum alloy or ZnAlMg-coated steel, from precursor solutions containing Al3+-only, Zn2+-only, and both Al3+/Zn2+ ions-free, respectively. To do so, anodic currents were applied to the metallic substrates in the first step, to in-situ produce Zn2+ and Al3+ in solution near the galvanized steel and aluminum alloy surface, respectively. Cathodic currents were then applied to ensure the cathodic deposition of Zn-Al LDH film when the anodically dissolved ion and another already existed ion in the precursor solution react with the in-situ cathodically produced OH-. Similar approach was applied on ZnAlMg-coated steel, on which both the Zn2+ and Al3+ ions were produced in the first anodic dissolution step, and these ions react with the in-situ produced OH-in the second cathodic deposition step to form LDH coating. The resulting LDH coatings exhibit a unique vertically grown morphology that ensure them be suitably used as pretreatment layer of the subsequent epoxy coatings, and thereby improving the corrosion resistance of the entire coating system. Additionally, incorporated corrosion inhibitors into the LDH pretreatment layer can further enhance the anti-corrosion performance of the coating system. This series of work developed a new approach to prepare vertically grown LDH coatings using a rapid and mild in-situ two-step electrochemical method, reducing or even eliminating the requirement for externally added metal ions during the preparation process.

Anti-rust oils (ARO) is a high effi ciency-cost anti -corrosion technique to inhibit the atmospheric corrosion of metal parts and equipment. However, in contaminant or coastal environments, salt particles, aerosol, CO 2, SO2, etc., may intrude into the oil layer, leading to the early failure of AROs. In this work, we first prepared a kind of ARO made of sodium petroleum sulfonate (SPS) inhibitor and white oil, then coated the ARO on a mild steel plate to investigate the deterioration process of AROs beneath saline water droplets by Quartz cryst al microbalance (QCM) and electrochemical mapping techniques. It shows that the SPS concentration is crucial to the ARO inhibition property. When the SPS content is lower than its critical micelle concentration (CMC), saline droplets may permeate the barri er formed by the nonpolar paraffin groups of SPS and then adsorb on the steel surface, resulting in localised corrosion. However, once the SPS content exceeds its CMC, the saline droplets will be emulsified and captured in the oil phase by the reverse mice lle effect, thus inhibiting the corrosion of steel substrates. The microstructure of the oil -water interface was characterised by micro-infrared spectroscopy techniques, showing that the surfactant molecules can transform water molecules from free to bonde d water molecules through oriented adsorption, thus offering protection against the intrusion of saline droplets. In contrast, concentrated NaCl saline(>0.5 droplets may disrupt the bonded state of water molecules, decreasing the arresting ability of AROs on saline droplets. Moreover, wire beam electrodes (WBE) and thin electrical resistance (ER) techniques were employed to probe the atmospheric corrosion of mild steel under AROs, and it evidenced that the ER is better at evaluating the inhibition performan ce of AROs than traditional electrochemical methods.

This work provides a study for crystallographic orientation dependent electrochemical corrosion rate of aluminum employing an ab initio model with inputs from first-principles calculations. Results show that the sequence of electrochemical corrosion rate is in the order of (111)  (410)  (331)  (221)  (321)  (211)  (110)  (100)  (210)  (320)  (310)  (311) for aluminum under marine environment. The predicted corrosion current densities for (111), (110) and (100) surfaces are in agreement with the previous experimental studies. The lowest corrosion current density of (111) surface is due to its lowest surface energy density and highest free energy of adsorbed hydrogen atom. The electron back -scattered diffraction analysis and atomic force microscope assessment of pu re aluminum were carried out to further evaluate the corrosion resistance for surfaces of different crystallographic orientation. The effects of alloying on electrochemical corrosion rate are further investigated employing this model with results validated via the polarization curves of alloyed aluminum. Commonly used alloying additions of Si and Mg were chosen to verify the theoretical prediction. This study could predict the corrosion behavior of different binary Al alloys, provide theoretical guidance for screening effective additive elements to improve the corrosion resistance and is expected to accelerate the design of corrosion-resistant Al alloys.

The triboelectric nan ogenerator (TENG) is based on the triboelectric effect and electrostatic induction, which provides an effective method to collect mechanical energy such as tide and wave in the marine environment into electrical energy. Compared with sacrificial and impressed current cathodic protection, this method can use green energy for the marine metal corrosion protection. However, the output performance of TENG mostly depends on the friction materials of the electrodes. The composite of PDA and MXene was used to cons truct PDMS sponge structure for the TENG electrode, and the process of electric charge excitation and transfer is investigated. The results indicates that the customizing sponge structures have large pores with enhancing contact friction and extraordinary pressure resistance. The charge can transfer between different electrodes due to the difference of the dielectric properties, and the Mxene act as good conductor for the transfer. Besides providing electric energy for monitoring instruments and corrosion protection, the sponge TENG also has sensitive response of the different pressure, and the electric current value reflects the strength of the impact force, which can act as the indicator wave level.

Anti-rust oils (ARO) is a high efficiency -cost anti -corrosion technique to inhibit the atmospheric corrosion of metal parts and equipment. However, in contaminant or coastal environments, salt particles, aerosol, CO 2, SO2, etc., may intrude into the oil layer, leading to the early failure of AROs. In this work, we first prepared a kind of ARO made of sodium petroleum sulfonate (SPS) inhibitor and white oil, then coated the ARO on a mild steel plate to investigate the deterioration process of AROs beneath saline water droplets by Quartz crystal microbalance (QCM) and electrochemical mapping techniques. It shows that the SPS concentration is crucial to the ARO inhibition property. When the SPS content is lower than its critical micelle concentration (CMC), saline droplets may permeate the barrier formed by the nonpolar paraffin groups of SPS and then adsorb on the steel surface, resulting in localised corrosion. However, once the SPS content exceeds its CMC, the saline droplets will be emulsif ied and captured in the oil phase by the reverse micelle effect, thus inhibiting the corrosion of steel substrates. The microstructure of the oil -water interface was characterised by micro-infrared spectroscopy techniques, showing that the surfactant molec ules can transform water molecules from free to bonded water molecules through oriented adsorption, thus offering protection against the intrusion of saline droplets. In contrast, concentrated NaCl saline(>0.5 droplets may disrupt the bonded state of water molecules, decreasing the arresting ability of AROs on saline droplets. Moreover, wire beam electrodes (WBE) and thin electrical resistance (ER) techniques were employed to probe the atmospheric corrosion of mild steel under AROs, and it evidenced that the ER is better at evaluating the inhibition performance of AROs than traditional electrochemical methods.

In this work, oxide layer formation and localized corrosion of the aluminium alloy AA5083 -H111 in a simulated dynamic seawater/air interfacial zone and a full seawater immersion zone was investigated with electrochemical impedance spectroscopy (EIS), focused ion beam, transmission electron microscopy and energy dispersive x -ray spectroscopy. As compared with the full immersion zone, the interfacial zone showed hig her oxide film thickness and charge transfer resistance, which was attributed to the high oxygen flux in that zone. Localized corrosion arose from IMPs that posessed an Al-Fe phase and a Ti enriched phase. The EIS data were fitted by power law model, which allowed to plot the resistivity profiles of the oxide films.

In order to predict the gen eral corrosion damage to metals and alloys, the acquisition of various kinetic parameters is of paramount significance. Electrochemical impedance spectroscopy (EIS) is a crucial technique for revealing the electrode kinetics. Equivalent circuit model compo sed of circuit components to analyze the values of components from EIS data, effectively distinguishes the “better or worse” corrosion resistance of different materials, but is short of dynamic information. Macdonald et al. developed a promising approach to optimize EIS data to acquire the kinetic parameters (such as transfer coefficients and rate constants, diffusion coefficients of defects) for passivated electrodes on the basis of the Point Defect Model (PDM). However, it is difficult to obtain the unequivocal values from optimization of EIS data because of too many unknowns. Herein, a theoretical method for independently estimating some parameters in the PDM from Mott -Schottky analysis is developed, such as polarizability α, β, and transfer coefficient of α5, α6. We reduce the number of unknowns in the optimization procedure, and thereby greatly improving the ability of the optimization procedure to determine accurate values for the remaining parameters in the PDM. For iron in borate buffer solution, the transfer coefficients of α2, α3, α5, α6 and α7 are determined as 0.277, 0.003, 0.146, 0.219 and 0.961, and the rate constants of k2 0、k3 0、k5 0、k6 0和k7 0为 6.626× 10-12 mol/(cm2 s), 6.492× 10-6 mol/(cm2 s), 6.075× 10- 8 mol/(cm2 s), 5.512× 10-7 mol/(cm2 s) and 10-5~10-3 mol/(cm2 s), respectively. The electric field strength within passive film of iron is independent of the applied potential and pH of solution, with a value of 4.474 MV/cm. DFT calculations and exp eriment results validate the obtained rate constants from optimizing EIS data.

In this talk, a discussion on EIS data for corrosion resistant materials design and corrosion evolution studies will be presented based on the recent progress in our lab. First, t he impedance response by an oxide film on metals can be interpreted in terms of in-depth distribution of electrical properties, and thus by suitable analyzation in EIS data the film thickness and resist ivity distribution inside the oxide film can be derived based on exponential or power-law distributions in resistivity [1]. Based on this, a corrosion resistant oxide film may be a key in developing corrosion-resistant Pb-free Sn-based solders. Moreover, EIS has been employed to understand the degradation behavior of a rust -preventive oil in contact with NaCl electrolyte, with a focus on analyzing the electrochemical responses that correspond to a different frequency range in the obtained EIS spectra [2]. B esides, EIS is a powerful characterization method to unravel the electrochemical process in timescale, and EIS has been found as a powerful tool in analyzing the adsorption and desorption behavior of corrosion inhibitors under acid conditions.

In this study, the corrosion behavior of 6063 alumi num alloy in Na 2SO4- Na2HPO4-H2O system was studied by EIS measurements. As shown in Fig.1, with the developing depth of corrosion pits, the impedance level had shown a sharp decrease with time. A middle frequency inductive loop was found in the Nyquist plo t after 72h immersion, while in the initial (12h) and final (168h) stage of the immersion, the Nyquist plot showed two capacitive loops with absence of inductive behavior. Similar inductive loops had been reported on the EIS data in alkaline media (KOH). I n order to explain the occurrence of inductive behavior in molten salt hydrate systems, six type of different media with pH value equals 3.5, 7 and 9 were prepared, Na 2HPO4 and Na2SO4 were added separately to study influence from different type of anions. Nyquist plots in Fig.2 gave a clear conclusion that the Na 2SO4 media were more sensitive to pH changes, a low frequency inductive loop was found in the acid media showing early stage of pitting corrosion. Inductive loops were found in Na2HPO4 systems under three different pH value media. Considering the hydrolysis reaction of HPO 42-, the interim inductive behavior of impedance data in Na 2SO4-Na2HPO4-H2O system can be explained by the hydrolysis reaction of HPO42-, while the existence of SO42-resulted in a competitive reaction on the sample surface. Fig.1 Morphology of the corroded area and the corresponding Nyquist plot after (a) 12h (b) 72h and (c)168h immersion Fig.2 Nyquist plot of Al-alloy samples in saturate Na2HPO4 and Na2SO4 solutions with different pH values

Cathodic protection is widely used for corrosion protection of steel bars in concrete. However, in the concrete conta minated with Cl -, the protective effect of cathodic protection is reduced. Meanwhile, the cathodic protection at a certain potential accelerates the hydrogen evolution rate and hydrogen permeation rate on the surface of steel bars. This paper uses arginine -trisodium phosphate complex (LA -P) as a migration corrosion inhibitor (MCI) and a simulated concrete solution containing 3.5 wt% NaCl as the corrosion environment. The corrosion behavior of HRB400 steel with the addition of MCI are studied through polariz ation curves, electrochemical impedance spectroscopy (EIS), and scanning vibration electrode technology (SVET). Besides, the morphological changes of the steel surface before and after corrosion are compared by atomic force microscopy (AFM). The binding of LA-P and Cl - is confirmed by ion chromatography (IC). Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), raman spectroscopy, and X -ray photoelectron spectroscopy (XPS) are applied to study the migration characteristics and adsorptio n behavior of MCI under cathodic polarization conditions. The inhibitory effect of MCI on hydrogen permeation process is verified through the Devnathan-Stachurski double cell technique. The results indicate that the application of cathodic protection enhances the adsorption of LA-P on the surface of steel and reduces the corrosion rate. Moreover, the hydrogen evolution rate on the surface of the steel is decreased, which effectively reduces the hydrogen permeation current. The damage of Cl-to the passive film of steel is inhibited by the capture effect of LA -P on Cl -,which reduces the corrosion rate of steel. The excellent synergistic effect of MCI and cathodic protection has broad application prospects in inhibiting steel corrosion in Cl-polluted concrete environments.

The corrosion behavior of B4C/6061Al in deionized water and different H3BO3 concentrations (500, 2500, 5000 and 10000 ppm) and temperatures (20 ° C, 50 ° C and 90 ° C) was investigated by combining experimental and modelling studies. In deionized water B4C/6061Al forms γ-AlOOH and Al(OH)3. Increasing temperature will promote γ-AlOOH formation whereas an increase in H3BO3 concentration will dissolve corrosion products. The corrosion resistance decreases from 20 ° C to 50 ° C but increases at 90 ° C, peaking at 2500 ppm H3BO3 for all temperatures. B4C particles in the aluminum matrix cause micro-galvanic effects, increasing the corrosion rate.

Due to the exhibited promising comprehensive properties [1], High-entropy alloys (HEAs) has received increasing attention ever since it was first reported. Among various HEAs, precipitation -hardened HEAs (PH -HEAs) has exhibited outstanding mechanical properties. The extensively studied HEAs hardened by secondary phases such as L12 and B2 phase have high-strength and large-ductility at room temperature. However, secondary phase in most reported HEAs with good strength and ductility usually contains harmful elements to corrosion resistance, such as Al [2], and the application was restricted. Ni 3Ti phase eliminates the negative effect of Al on passive film and has good strength and plasticity. Different from the widely studied corrosion behavior of B2 [3] and L1 2 phase [4], Ni 3Ti phase received little concern. To design corrosion resistan t Ni 3Ti-hardened HEAs, it is necessary to study its corrosion behaviour. In this work, Ni3Ti-hardened Ni40Fe32Cr20Ti4Mo4 HEA (Ti4Mo4) was designed, and was produced via inductive arc melting furnace. Spherical Ni3Ti phase (SNPs, enriched in Ni, Ti with minor Fe and Cr) precipitated at grain interior, lamella Ni3Ti phase (LNPs, enriched in Ni and Ti) precipitated at partial grain boundary. Effect of Ni 3Ti phase in Ti4Mo4 on corrosion resistance and passive film properties in 15 wt.% NaCl, as well as mechanic al properties and crack initiation during tensile was investigated. Transpassivation potential of Ti4Mo4 reached 1.05 mVSCE, ultimate tensile stress was 1189 MPa, elongation was 27%. The continuous and protective passive film on whole surface resulted in t he good corrosion resistance, and no pits formed. The plastic deformation ability of Ni3Ti phase contributed to the good mechanical properties.

The "dual carbon" objective strongly promotes energy conservation and emission reduction. Each 10% reduction in an automo bile's weight correlates with an 8% decrease in carbon emissions, therefore making automobile lightweighting becoming a predominant trend in industrial advancement. Hot -formed steel has excellent plasticity and toughness, significantly reducing the weight of the vehicle body and facilitating lightweight construction while ensuring safety performance. Nonetheless, a significant issue with hot -formed steel is the substantial formation of oxide scale on its surface during heating. The binding force between the oxide scale and the matrix is inadequate. Consequently, it is imperative to suggest a solution to mitigate the aforementioned deficiencies. Our study has created an innovative, cost - effective anti-oxidation technology for hot-formed steel, tailored to the specifications of current production lines, to address the issue of oxide scale detachment, facilitate independent research and development, thereby expediting the strategic advancement of lightweight automobiles.

As electronic products advance towards superior performance and higher integration, electronic materials, particularly solder metals, encounter complex and abnormal corrosion issues during manufacturing processes and actual service, significantly affecting product reliability. This paper begins with the study of the Sn-Ag system, using practical Sn -Ag solder alloys to investigate the corrosion and dendrite growth processes. The fundamental thermodynamic and kinetic principles involved are revealed. The mechanisms by which various factors influence selective corrosion behavior are identified, including operating voltage, temperature and humidity, pH value, and flux. Subsequently, specially designed Sn -Ag alloys were empl oyed to further examine the critical role of intermetallic compounds such as Ag 3Sn in the selective corrosion process. Based on these findings, evaluation methods and a life prediction model for solder corrosion failure were established and applied to the study of selective corrosion in more complex ternary and quaternary multi-metal systems.

In most environment, the corrosion of commercial Al alloys is associated with the galvanic corrosion between anodic and cathodic regions due to the existence of second phases. In recent work, amorphous Al alloys were produced by magnetron sputtering to improve the strength and corrosion resistance simultaneously. Specifically, the passivation mechanism of amorphous Al-Mn and Al-Mn-Mo alloy thin films in NaCl solution were studied detailly. The origin of passivity in amorphous Al -Mn alloys were investigated by combining experiments and molecular dynamic simulations [1]. The surface analysis confirmed that Mn did not participate in the surface oxidation. It is believed that Mn dissolution can increase the free volume at the metal/oxide interface, leading to the formation of a dense, thin oxide layer on the surface of Al-Mn alloys. Moreover, the effect of alloying concentration on the corrosion behaviors of Al -Mn-Mo alloys were investigated [2]. It is expected that the pitting potential of alloys increased with Mo. It is interesting to note here that Mo addition to the alloys can reduce the defect density of the passive film, a higher oxidation state of Mo ions (+4 and +6) can create more free electrons to combined with oxygen vacancies.

In the last decade, integrated computation of corrosion has made significant progress towards the atomic -scale clarification of corrosion mechanisms and computer-aided designing of advanced materials with excellent cor rosion resistance. We focuses on the theoretical calculation methods and developing tendency in corrosion study, and some specific applications are presented. First -principle calculations combined with molecular dynamics method, peridynamic theory and finite element method provide multiscale models to investigate micromechanisms of stress corrosion cracking and hydrogen -induced cracking. Calculations of passivity and passive film breakdown are elaborated through point defects diffusion and its correlation of the energy level degeneracy. Some vital kinetic parameters for metal electrode are estimated by combining first -principle calculations with electrochemical impedance spectroscopy analysis. Moreover, the artificial intelligence technology is pointed out h ow the computer can pave the way of predicting corrosion degrees as well as designing new corrosion resistant materials. To get better and efficient development of integrated computation of corrosion, extensive cooperation and powerful data infrastructure are needed by stronger collaboration in the future.

This study focuses on R5 and R6 grade mooring chain steels (with strengths of 1000 MPa and 1150 MPa, respectively). It investigates the effect of hydrogen charging potential on the susceptibility to hydrogen embrittlement of these steels through slow strain rate tensile experiments conducted at different cathodic potentials. Fracture morphology was examined using a scanning electron microscope (SEM), and further analysis was performed using electron backscatter diffraction (EBSD) techniques and hydrogen thermal analysis. The experimental results indicate that cathodic hydrogen charging significantly reduces the plasticity of the mooring chain steels, with sensitivity to hydrogen embrittlement increasing as the potential shifts negatively. However, the yield strength and tensile strength of the specimens are not significantly affected. When the cathodic polarization potential approaches the corrosion potential, ductile fracture predominates. As the hydrogen charging potential shifts negatively, the hydrogen content increases, leading to an enlarged brittle area, with intergranular fracture gradually becoming dominant. One difference between R5 and R6 grades is that R5 grade does not exhibit a clear critical potential, whereas the critical potential for R6 grade is -1150 mV. EBSD results show that after stretching, the grains are significantly refined and elongated in the stretching direction, with grain rotation resulting in changes in crystal orientation. As well as, the KAM values increase significantly. Overall, these findings provide impo rtant insights into the safety of using R5 and R6 grade mooring chain steels and offer theoretical support for the cathodic protection research of high-strength mooring chains in seawater environments.

Coal makes up a big portion of energy consumption in China, which is guaranteed by fully mechanized mining technology for efficient and safe production. With the increasing of chain steel strength, hydrogen embrittlement become s a key problem in the lightweight of mining equipment in coal mines. In this experiment, two kinds of mining chain steel were tested. Combined with hydrogen thermal analysis and slow strain rate tensile testing on notched specimens, the influence of hydrogen permeation on the mechanical properties of high strength mining chain steel in coal mine service environment was explored. The results demonstrat e that as the corrosion time increased, the hydrogen content invaded into the material also increased, while the fracture stress correspondingly decreased, reaching the most extreme values after 21 days of corrosion. At a corrosion time of 21 days, the hydrogen content in the 21# and 51# chain steels reached their peak values of 0.336 wppm (21#) and 0.129 wppm (51#), respectively. The fracture stress dropped from the initial values on uncorroded specimens of 2178 MPa (21#) and 2114 MPa (51#) to the lowest values observed during the experiment, which were 1979 MPa (21#) and 1859 MPa (51#), respectively. The fracture analysis shows that after the same time of corrosion, the severity of intergranular fracture in the fracture of 51# mining chain steel is greater than that of 21# mining chain steel, and the reduction of fracture stress is also greater than that of 21# mining chain steel, indicating that 51# is more sensitive to hydrogen.

Hot stamping steel is the largest amount of high strength steel products used in white body. In order to improve the corrosion resistance and oxidation resistance of hot forming steel, a metal coating is usually hot-dipping on the surface of hot stamping steel, such as aluminum silicon coating (AS) and galvanized coating (GI). In order to study the effect of different heating time on the corrosion resistance of GI coating, the 22MnB5 steels with GI coating were heated under 3 min to 10 min at 900 °C. The corrosion resistance of the coating was evaluated by electrochemical test and neutral salt spray test. The results show that GI coating was composed of Fe3Zn10 phase and α-Fe (Zn) phase after heating at 900 °C. With the increase of heating time, the F e content in the coating increased gradually, and the impedance of the coating increased gradually. After 20 days of neutral salt spray test, white rust still appeared on the surface of the coating, and there was no corrosion to the substrate. During the corrosion process, the zinc-rich phase was corroded first. In conclusion, after heatment the GI coating still has good corrosion resistance, but the cathodic protection performance of the coating decreases with the increase of heating time.

In economically developed areas with great energy demand, the available land resources are gradually decreasing, and overhead power transmission lines are being replaced by underground cables. This has led to inevitable intersections and parallel layouts with buried oil and gas pipelines in the same corridor. The electromagnetic fields generated by high -voltage cables may cause varying degrees of interference to nearby metallic pipelines and other electrical equipment, and may even lead to safety incidents. This paper takes an actual case where a 110 kV high - voltage power cable parallels and crosses with a buried pipeline as the research object, and through numerical modelling with CDEGS software packages, comprehensively analyzes the electromagnetic interference effects of power lines on adjacent pipelines under steady-state balanced operation, steady-state unbalanced operation, and short-circuit fault conditions. The modelling results show that under the steady -state conditions of balanced operation of double -circuit power cables and unbalanced operation of single-circuit with a 5% imbalance, the AC voltage, touch voltage, and AC current density along the pipeline are all significantly lower than the corresponding safety limits, and there is no risk of electric shock s afety to human or AC corrosion to pipeline. During the fault operation of the power cable, especially when the cable sheath protector is broken down and grounded, the maximum touch voltage along the pipeline exceeds the safety limit value for transient con ditions, reaching more than 2 times, indicating a risk to personal safety. Further modelling results show that at the intersection of the cable and the pipeline, grounding the pipeline through a solid -state decoupler connected to a zinc ribbon can effectively mitigate this safety hazard.

The reduction behav ior of rust layer formed on carbon steel and on Cr - containing steels has been investigated in flowing thin electrolyte layer with 3.5% NaCl solution, via potentiodynamic polarization curve, EPMA, Raman spectroscopy, XRD, and XPS. The cathodic potentiodynam ic polarization curves of carbon steel and Cr - containing steels were carried out in flowing thin electrolyte layer with vacuum environment, for eliminating the reduction reaction of oxygen. Results show that the cathodic reaction of Cr -containing steels wa s inhibited by concentration of Cr in the inner rust layer, and the reduction of rust layer formed on Cr-containing steels was also inhibited. The constituent of rust layer formed on carbon steel was the same with that of Cr -containing steels. However, the amount of Fe 3O4 in the rust layer formed on carbon steel was higher than those formed on Cr -containing steels after cathodic potentiodynamic parization curves. It indicates that the reduction of Fe 3+ was suppressed for Cr -containing steels. Cr exited in the form of Cr 3+ in the corrosion product, participating in the transformation of corrosion product.

Energy transport safety has always been the focus of China. Among them, the study of buried pipeline integrity is an important branch of the s ecurity field. Therefore, coating and cathodic protection as two major barriers to protect buried pipelines has been studied extensively. Considering that mechanical damage may occur to the pipeline during transportation and installation, the performance of coating against cathodic peeling becomes particularly important. At present, the commonly used materials such as 3PE, FBE and 3LPP in long -distance pipelines have different degrees of problems. Therefore, the emergence of a new type of solvent -free epoxy glass reinforced plastic provides a feasible potential option to solve this problem. In this paper, the cathodic peeling resistance of the new coating was tested, and it was found that it fully met the requirements of SY/T 5918 -2017 standard on the cathod ic peeling resistance of solvent-free liquid epoxy materials. At the same time, we modeled the cathodic peeling degree and time, and found that they basically showed the form of a parabola equation (x=c*ta), the index a was close to 0.5, and the peeling ra te should be controlled by ion migration. At the same time, the impact of hydrogen evolution reaction occurring in the cathode was also analyzed. In summary, this paper demonstrates the cathodic peeling resistance of a new type of material, and demonstrates its positive impact on pipeline integrity. This new coating technology and service evaluation will be further innovated and improved, which will promote the development of coatings towards a more intelligent and environmentally friendly direction, in ord er to adapt to the changing application scenarios and market environment.

An inspection of a ship revealed severe corrosion in the BFe30 -1-1 cupronickel heat exchange tubes of the auxiliary condenser. After performing eddy current testing on these heat exchange tubes, areas with significant corrosion were selected. Macro observation, chemical composit ion analysis, energy dispersive spectroscopy (EDS), and Raman spectroscopy were used on the selected samples to detect corrosion products and analyze the causes of corrosion. The experimental results indicate that the incomplete removal of oil films during production led to the formation of residual carbon films during heat treatment, which in turn triggered electrochemical corrosion, ultimately becoming the primary factor for the extensive corrosion of the cupronickel tubes. Additionally, residual water st ains after operation are also an important cause of accelerated corrosion in the cupronickel tubes.

EIS proves to be a versatile and robust technique, adept at unravelling concurrent physical and chemical processes within electrochemical systems. Despite its advantages, extracting meaningful information from EIS faces challenges, as impedance spectra must adhere to causality, linearity, and stationarity. These aspects are sometimes overlooked due to the increasing automation of the process and the ease of data fitting. In electrochemistry, processes often exhibit nonlinearity, such as the exponential relationship between current and pote ntial. Time -induced inherent changes of the electrode, typical in corrosion, introduce non -stationarity during EIS measurements. It's crucial to recognize that stationarity in the measured electrochemical system limits the use of EIS for high-to-low frequency measurements as electrode changing can be expected in the time frame that measurements are done. Additionally, inherent noise in EIS measurements, stemming from hardware and often neglected, complicates the fitting of electrical equivalent circuits. Ad dressing these complexities, our research group at VUB pioneered the Odd Random Phase multisine excitation signal EIS (ORP -EIS). This technique selectively excites specific odd harmonics, allowing for the quantification of nonlinearities, nonstationarities, and noise. Access to this information enhances the reliability of data and leads to a better understanding of signal -to-noise ratios, facilitating more accurate fitting. While EIS demands linearity, many electrochemical processes inherently exhibit nonlinearity. Our group recently developed a method to detect and quantify nonlinear distortions, estimating the Best Linear Time -Varying Approximation (BLTVA) for nonlinear time - varying systems. A cutting -edge advancement is the operando ORP -EIS, facilitating EIS on rapidly evolving systems over time. This innovation enables EIS measurements on all non-stationary systems, opening novel applications like monitoring fast battery charging, studying the corrosion and protection of magnesium, assessing inhibitor actions, and observing the initial ingress of water and ions in organic coatings. Furthermore, operando ORP -EIS extends its utility to monitor surface modification processes directly. Unlike classical EIS, which is a post -mortem analysis, operando EIS allows us to observe processes like anodizing or the application of conversion systems in real-time. Acknowledgements: the authors acknowledge colleagues of Electrical Department and SURF research group for the development of ORP EIS.

Proton exchange membrane water electrolysis (PEMWE) and proton exchange mem brane fuel cells (PEMFC) are most attractive approaches for green production and utilization of hydrogen energy. The current collector (CC), known as bipolar plate, is one of the most crucial components in PEMFC and PEMWE. The CC should have relatively low cost, good mechanical qualities, high electrical conductivity and strong corrosion resistance to meet the commercial demand. In terms of cost, mechanical strength and manufactures, stainless steel can be a favorable CC material compared to traditional gra phite material. However, the electrical conductivity and corrosion resistance of stainless steel are usually not sufficient in PEMWE and PEMFC working environment. In this work, we focused on the development of advanced surface engineering to largely incre ase corrosion resistance and decrease contact resistance of stainless steel for CC in PEMWE and PEMFC. Firstly, an electrochemical superpassivation was developed to enhance the corrosion resistance of various grades of stainless steel s. It is indicated th at the electrochemical superpassivation is able to reduce the corrosion current density of stainless steel from 6.08 μA/cm2 to 0.042/μA/cm2 in the same testing solution, due to the favorable chemical composition and structure of the passive film. In order t o low the contact resistance for stainless steel, a dispersive film of platinum nanoparticles was electrodeposited onto the elelctrochemically superpassivated stainless steel. It is demonstrated that the interfacial contact resistance (ICR) of the stainless steel with platinum deposited for 60 s was as low as 10 mΩ·cm2 at 1.4 MPa compression force, which is promising to be adapted in PEMFC working environment.

众所周知,阴极保护是海洋环境最有效的防护措施之一,在船舶、海岸工程、 采油平台、海底管线、跨海大桥、海底隧道等等多种海洋工程设施的安全运行中,起 到了举足轻重的的作用。然而,随着“深远海”的开发,复杂条件、复杂环境、特殊金属 材料等层出不穷,对于阴极保护的要求更高更细致。对于一些特殊的局部腐蚀:比如 孔蚀、缝隙腐蚀、电偶腐蚀,对于特殊环境:干湿交替、深水深地、涂层屏蔽、管线 接头等部位的阴极保护,提出了挑战。 本文针对涂层破损(保护界面不均匀)、海水海泥岩石层长尺试样(环境不均 匀)、深海温跃层(环境不均匀)以及干湿交替区(环境不均匀,且变化)等海洋复 杂环境,采用数值模拟优化设计与保护效果评估,从阴极保护电池极化动力学角度, 提出解决策略。针对海洋典型微生物腐蚀采用恒电量、恒电位和变电位阴极极化探讨 了对硫酸盐还原菌和铁氧化菌的保护电位、生物膜下腐蚀等的保护效果。

Use of corrosion inhibitor is one of the possible way of controlling CO 2 corrosion in oil and gas and presently in connection with CO 2 capture and storage application. Many commercial inhibitors used today have toxic constituents and overall composition is not environmental friendly. Hence, there is significant interest to explore green i nhibitor chemistries that can provide comparable inhibitor efficiency similar to presently used molecules. In this study, the inhibition ability of black tea extract (BTE) on the corrosion behavior of 1Cr carbon steel was investigated in detail. An important step is the identification of the appropriate extraction method to produce the inhibition chemistry, which was explored and produced solid extract through vacuum distillation process. Different filtering process was also investigated as a part of this and connection to inhibition efficiency. UV spectroscopy and HPLC was used for analysing molecular constituents of BTE. DFT modelling was carried out to understand absorption energy related to various constituents with reference to water. For corrosion investigation, tests were conducted at atmospheric pressure in a 1wt.% NaCl solution saturated with CO2 at 40 and 60 oC with different inhibitor concentrations (from 50 to 4000 ppm). Linear Polarization Resistance (LPR) and electrochemical impedance spectros copy(EIS) were used to study the electrochemical behavior. Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), and Transmission electron microscopy were utilized to analyze the phase composition and morphology of the film forme d. Results showed changing the morphology and properties of the formed corrosion layers as a result of materials protection from corrosion by BTE. Moreover, extract synthesis approach found to affect the inhibitor efficiency. Increase in temperature found to increase inhibitor efficiency.

Loading capacity and controlled release are two important features of smart corrosion inhibitor nanocontainers. In this presentation, we highlight recent findings of our group in modifying the surface of halloysite nanotubes (HNTs) and developing a tube end stopper to increase loading capacity and control benzotriazole (BTA) release. To increase BTA loading capacity, we employed a combination of two approaches: heat treatment and Zn 2+ cation preadsorption, a method previously published by our team.[1] Besides, to control the release of BTA, two types of tube end stoppers have been investigated, including a complex between zinc ion and BTA (Zn -BTA) and a complex between ferric ion and tannic acid (Fe -TA). The results showed that surface treatment and modification increased the BTA loading capacity of modified HNT to 15.5 wt.%, much higher than the 4.57 wt.% of the original HNT. Moreover, the BTA release process was also controlled by either the Zn -BTA or Fe -TA stoppers. Both stoppers exhibited slow BTA release rates from the nanocontainers in neutral environments and gradually increased as pH decreased. As a result, the smart corrosion inhibitor nanocontainer systems Zn -BTA@BTA/modified-HNT and Fe -TA@modified-HNT not only show excellent corrosion inhibition effects but also exhibit active corrosion inhibition properties when applied as additiv es in epoxy coatings on carbon steel, as demonstrated by electrochemical measurements and salt spray testing.

2024 aluminum alloy, a member of the Al -Cu-Mg alloy family, has piqued research interest due to its extensive application in aerospace, ocean environment, oil and gas, and other industries, but its high Cu content, the major alloying element, is a major drawback to its use, especially in applications requiring high corrosion resistance. This is partic ularly problematic in chloride systems containing oxygen. Herein, we developed a protection strategy for 2024 Al alloy in an acid-chloride environment using natural tetrahydropalmitine (THP) isolated from Corydalis yanhusuo, a traditional Chinese medicine. THP was effectively characterized from its 1H NMR, 13C NMR, and FTIR spectra, and its anticorrosion potentials were methodically investigated by electrochemical, gravimetry and theoretical experiments. Upon the addition of THP to the test system, EIS meas urements revealed a steady increase in the Nyquist semicircles, as well as the Bode impedance and phase angle plots, attaining an optimum inhibition efficiency of 91.1% at 2.0 g/L THP. The Tafel plots manifested mixed-type anticorrosion effects with domina nt cathodic properties, ascribed to the ordered shielding effect of both the hydrogen evolution reaction and the oxidation of oxide-free ions. Time -dependent corrosion assessment showed that the surface of 2024 Al alloy remained increasingly protected with time up to a maximum of 413 Ωcm2 after 168 h. This was attributed to a combined effect of the formation of stable oxide films and adsorbed THP on the surface of the metal surface. SEM afforded the proof of THP adsorption on 2024 Al while XPS offered clari ty into its anticorrosion mechanism. Conceptual DFT parameters, molecular electrostatic potential and molecular dynamics simulations were performed to understand the inhibition process of THP on Al surface. Generally, THP was proven to be a viable and sust ainable bio-based anticorrosion material for the protection of aluminum alloys.

Poly (2-vinyl pyridine) (PVP), carboxymethylcellulose (CMC), and poly (2 - hydroxyethyl methacrylate) (PHEM) are three polymeric inhibitors whose anticorrosion properties were evaluated using both experimental and computational methods on mild steel in 0.5M H2SO4. The weight loss, corrosion inhibition, efficiency, degree of surface coverage, adsorption studies, electrochemical tests, kinetics and thermodynamic analysis, and computational studies were determined. The Gibbs free energy was determined using the Frumkin adsorption model. The Arrhenius plots were utilized to determine the activation energy, and the transition state equation was utilized to determine the enthalpy and entropy. Computational studies utilizing the molec ular dynamics (MD) simulation were conducted using the Forcite module tool as contained in Material Studio software (7.0). The results demonstrated that the adsorption mechanism was temperature -dependent, as the polymer composite's protection effectiveness increased as temperature rose. Temperature and concentration increases were found to correlate with increases in surface angle, weight loss, and corrosion inhibition efficiency. PVP/CMC blend (1:3) at the concentration of 3.0g/l exhibited the highest inhibition efficiency at 24 hours, with 96.22 %, while PVP/PHEM (1:1) had the lowest, with 40.74 at 0.5g/l concentration at 168 hours. The results of the adsorption experiments were in agreement with the Freundlich, Langmuir, and Temkin isotherms, with nearly unit values and a linear graph obtained for each polymer blend. According to computational studies, all of the polymer blends showed a negative binding energy and a positive interaction energy, suggesting strong corrosion inhibition efficiency. With conce ntration, temperature, and exposure time having significant effects on their inhibition efficiency, these results validate the potential of the polymer blends as mild steel corrosion inhibitors.

In line with the use of nontoxic, biodegradable, green and sustainable materials for corrosion inhibition, we present a comprehensive evaluation of three natural phytocompounds, namely synephrine, troxerutin and epigallocatechin gallate (EGCG), which were correspondingly isolated from immature bitter orange, sophora flower and green tea leaves, as environment friendly and cost -effective corrosion inhibitors for steel in 1 M HCl solution. Following their isolation, the phytocompounds were un ambiguously characterized using FTIR and NMR spectroscopies before subjection to a series of experimental (EIS, potentiodynamic polarization (PDP), and SEM) and computational (quantum chemical parameters and molecular dynamics simulation) investigations. T he evaluations were achieved with respect to the concentrations of the phytocompounds, time of steel exposure to the acidic environment and the temperature of the test environment. Moreover, PD revealed that synephrine, troxerutin and EGCG exhibited mixed -type corrosion inhibition behavior for steel with strong dependence on their concentration. Troxerutin reached an optimum inhibition efficiency of 98% at 2 g/L while those for synephrine and EGCG were 84% and 78%, respectively. Furthermore, time -dependent EIS experiments showed that troxerutin manifested the highest impedance (492.9 Ωcm 2) at the start of immersion, and the value progressively declined to 63.5 Ωcm 2 after 168 h. Similarly, the value for EGCG decreased from 32.4 after 1 h to 10.1 Ωcm2 after 168 h. Synephrine initially increased from 140.7 Ωcm2 to 430.0 Ωcm2 after 2 h, and then slowly decreased to 27.9 Ωcm2 after 168 h. For the protection of steel, the phytocompounds followed the trend: troxerutin > synephrine > EGCG. The metallic protection was validated by the presence of adsorbed film layers on the surface of steel from SEM examination, whereas computational evaluations allowed the description of the adsorption characteristics and molecular interactions/orientations of the phytocompounds on Fe substrate. This study advance s the development of commercialized bio -based corrosion inhibitors.

The Sustainable Development Goal 12 advocates for producing, using, and consuming green and sustainable commodities. This advocacy and other such calls are mounting pressure on the oil and gas industries to transit and embrace green chemicals for their operations. Oil well acidizing is an important process for maximizing the output of oil reservoirs. Still, it involves the pumping of a highly concentrated acid solution into the wellbore thus making the use of inhibitors a necessity to reduce the corrosion damage. The inhibitive potential of a formulation consisting of aspartame (a derivative of aspartic acid and phenylalanine), potassium iodide (KI), and sodium dodecyl sulphate (SDS) for T95 steel in 15 wt.% and 28 wt.% HCl solutions have been explored at elevated temperatures. The formulation has been found to produce excellent corrosion inhibition with inhibitive performance increasing with a temperature rise. A 6.80 mM of the formulation can bring down the corrosion rate of T95 steel in 15 wt.% HCl solution from 186.37 to 14.35 mm/y and protect the metal surface by 92% at 90°C. The formulation performs even better in 28 wt.% HCl solution where 96% surface protection is achievable at 90°C. Corrosion inhibition by the formulation arises from the adsorption of aspartame molecules enhanced by KI and SDS leading to the formation of a dense hydrophobic layer on the metal surface. The formulation is a highly promising substitute for toxic acidizing corrosion inhibitors.

Biomass extract from the stem (CSE) and the leaves (CLE) of caladium tricolor were characterized by Fourier transform infrar ed spectroscopy and Gas chromatography - mass spectrometry. The CSE and CLE extracts were investigated for their corrosion inhibition efficacy and surface protection capability for mild steel under acidic conditions. The influence of corrosion inhibitor conc entration, temperature, and immersion time, on inhibition efficiency was evaluated using the gravimetric methods and potentiodynamic polarization methods. Inhibition efficacy for both inhibitors was dependent on concentration, temperature, and time, increa sing with increase in concentration and decreasing with increase in time of immersion and temperature of the system. Maximum inhibition efficiency of 98.92 % was obtained for CSE and 88.92 % for CLE at a concentration of 20 ml respectively after 24 hours o f immersion. The activation energy associated with this process indicated surface interaction as the main mechanism and positive values of enthalpy change confirmed the endothermic nature. The electrochemical parameters were calculated, and the inhibitor w as found to be mixed type. The adsorption of CSE and CLE on the metals was established by Fourier transform infrared spectroscopy and atomic force microscopy.

Low-cost lignin, as the second abundant bio -mass, poss esses many attractive advantages, like non-toxic, biodegradable, renewable, etc. The rich oxygen-containing groups of lignin, like -OH, -COOH and -CHO, provide a source for construction of dynamic bonds between lignin molecules and metal atoms. A series of lignin bio -based corrosion inhibitors were prepared based on grafting and copolymerization methods. Their corrosion inhibition performance for carbon steel in acidic and alkaline media were invesitaged using weight loss and electrochemical test. The in-situ SVET characterization was performed to monitor the change of corrosion inhibition ability with immersion time. Real -time AFM as well as many surface characterizations were carried out to illustrate the adsorption behavior and film-forming process of inhibitor molecules on metal surface. Adsroption phase-forming model was proposed to explain the superior corrosion inhibition performance of lignin bio -based corrosion inhibitors, which provided some novel insights for developing eco -friendly and broad-spectrum pH corrosion inhibitors from lignin-based biomass.

China is a major producer and consumer of Camellia oleifera, constituting more than 90% of global production. Camellia oleifera shells (COS) accounted for 50% ~ 60% of Camellia oleifera. Utilizing COS sensibly can reduce environmental contamination and enhance the circulating economy. Ultrasonic extraction and hydrothermal methods were used to prepare corrosion inhibitors with COS as raw material. The advantages and disadvantages of the two methods and the mechanism of action were compared in detail. The results show that the ultrasonic extracted inhibitor (COSE), had a short preparation time and great corrosion inhibition effect (90.5%, 1000 mg L -1), but with a large dosage. Carbon dots (CDs) obtained from the optimized preparation by the hydrothermal method can be used in 2/3 less amount and have slightly higher anti-corrosion properties (91.6%, 300 mg L-1), as confirmed by the results of the various tests. Moreover, CDs have excellent fluorescence characteristics than COSE, providing a good prospect for development. The results of this research can offer some reference value for the utilization and exploration of biomass resources.

Carbon quantum dots (CQD), one of the most common zero -dimensional carbon nanomaterial, show great applied pote ntial in the field of corrosion inhibition, owing to the advantages of wide sources, low price and environmental friendliness. In this work, a novel N -doped carbon quantum dots (N -CQD) were synthetized using a hydrothermal method with Camellia oleifera shells (COSE) as the raw materials. The chemical compositions of the as-prepared N-CQD were comprehensively analyzed by transmission electron microscopy (TEM), X -ray photoelectron spectroscopy (XPS), and infrared absorption spectroscopy (FTIR). The correspond ing corrosion inhibition effect of N-CQD for carbon steel in 1.0 M HCl solution was systematically studied by weight loss method, electrochemical impedance spectroscopy, and potentiodynamic polarization tests. Moreover, the protective effect and also hydro phobic properties of carbon steel modulated by N -CQD in HCl were further investigated by atomic force microscopy (AFM), contact angle tests, and also other techniques. Scanning electron microscopy (SEM) and X -ray photoelectron spectroscopy (XPS) were emplo yed to inspect the morphology and compositions of carbon steel influenced by N-CQD in 1.0 M HCl solution. All these above -mentioned results show that the novel green N -CQD prepared by COSE can effectively restrain the corrosion of carbon steel in 1.0 M HCl, which can always afford the inhibition efficiency of >87% within 20 -30 C. The deep analysis of electrochemical test results reveals that the N -CQD can inhibit both the cathodic and anodic reactions, thus leading to excellent anti-corrosion performance.

Rapeseed is the second largest oilseed crop in the world after soybeans. Effective utilization of its by-product of rapeseed meal (RM) can improve its economic value and promote the development of the rapeseed industry. Refluxed and ultrasonic rapeseed meal extracts (RRME and URME) were developed as novel steel corrosion inhibitors due to their chemical components containing substantial important organic compounds such as carbonyl compounds, flavonoids, and organic acids. The inhibition performances of both RMEs against cold rolled steel (CRS) corrosion in sulfamic acid (SA) medium were evaluated by weight loss method, electrochemical measurement, and surface characterization. It is found that these two RMEs can be regarded as hybrid inhibitors, which spontaneously form organic films with low fraction free volume (FFV) and low self -diffusion coefficient (self -D) on the CRS surface to achieve the highest inhibition efficiencies of 92.4 % and 95.4 % for RRME and URME, respectively, at the same concentration of 100 m g L -1. However, RRME has better inhibition performance and stability with the extension of immersion time in weight loss and temporal electrochemical impedance spectroscopy (EIS) tests. This study provides a new insight into the application of rapeseed meal as a novel steel corrosion inhibitor.

Considering the concept of green environmental protection, the by -product rapeseed cake meal (RCM) after oil extraction from rapeseed is recycled. A corresponding extract inhibitor (RCME) was prepared via reflux extraction with ethanol solution. The inhibition performance and mechanism of RCME in dichloroacetic acid (DCA) for steel were investigated using gravimetric, electrochemical, and surface characterization techniques. The r esults indicate that the C, N, and O elements form coordination bonds with Fe atoms upon the introduction of the RCME. The corrosion of the steel sheet surface was significantly suppressed. The maximum inhibition rate of 100 mg L -1 RCME can reach 92.3% at 40 °C. RCME acts as a mixed inhibitor in DCA, primarily affecting the anodic reaction through an “active site blocking effect” mechanism. The introduction of RCME increases the charge transfer resistance and exhibits a single-time constant. Theoretical calculations demonstrate that adenine, L - lysine, and their protonated forms possess active centers that facilitate bonding with Fe atoms. The entire molecule adsorbs onto the Fe(001) surface in a nearly flat orientation, thereby enhancing the contact area of the inhibitor molecule with the CRS surface and leading to excellent inhibition effects. This study offers experimental evidence supporting the use of agricultural and forestry waste in corrosion mitigation applications.

Macadamia integrifolia (MI) are highly popular due to their sweet kernel and rich nutritional value, and they are an ideal raw material for woody edible oil. At present, the planted area of MI in China accounts for 60.92% of the total planted area in the world, ranking the first in the world. The corrosion inhibitor of Macadamia integrifolia shell extract (MISE) was prepared by ultrasonic extraction and reflux extraction. and the effects of the two extraction methods on the inhib ition performance were investigated. The results showed that the corrosion inhibitors prepared by the two extraction methods showed excellent inhibition performance at 20-50 oC, and the reflux extracted inhibitor (RMISE) reached the highest inhibition efficiency of 93.6% at 50 oC when 200 mg L -1 of RMISE was added, while the ultrasonically extracted inhibitor (UMISE) reached the maximum inhibition efficiency of 93.1% at 40 oC. The inhibition efficiency of RMISE more than 90% when 60 mg L -1 was added. Nevertheless, UMIE must increase its concentration to achieve inhibition efficiency above 90%. The surface characterization revealed a significant reduction in surface roughness following the incorporation of two inhibitors. Additionally, the bonding of the active ingredient in MISE to Fe was detected by surface element analysis. In the future, we will also prepare Macadamia integrifolia shell-based plant inhibitors in more ways to further promote their efficient use in the field of metal corrosion inhibition.

To promote the efficient utilization of waste tobacco stems in agricultural systems and develop a highly effective, eco-system-friendly corrosion inhibitor for cold-rolled steel (CRS), this work focuses on the extraction and evaluation of tobacco stem extract (TSE) as a novel inhibitor. TSE was prepared using a simple and cost-effective reflux extraction method and tested for its corrosion inhibition performance on CRS in hydrochloric acid (HCl) media through both experimental studies and theoretical calculations. The results show that TSE contains multiple functional groups such as Fe-O, Fe-OH, C=O, and others, which contrib ute to its superior hydrophobicity and adhesive properties when adsorbed onto the steel surface. When 200 mg/L TSE was added, the inhibition efficiency was 91.1% at 40 °C. Its adsorption on the surface follows the Langmuir isotherm, and it acts as a mixed -type inhibitor. TOF -SIMS analysis reveals the presence of hydrocarbon peaks on the inhibited steel surface, with a significant number of N atoms and Fe -related bonds observed in both positive and negative ion spectra, confirming the effective adsorption of TSE molecules. The superior inhibition effect of TSE is attributed to its various components, with quercetin and nicotine identified as the primary active agents. In addition, Quantum chemical calculations and molecular dynamics simulations convincingly de monstrate that TSE exhibits significant anti -corrosion properties. This work provides new insight and opportunity for the development of Tobacco stem extract eco -friendly corrosion inhibitor for CRS.

Elastic stress has obviously influence on the passive film characterization and pitting corrosion behavior of stainless steel (SS). The small elastic tensile stress (16.63% σ0.2) would increase the protective performance of passive film and decrease the pitting corrosion sensitivity of 304 L SS in 3.5 wt% NaCl environment. As the elastic tensile stress increases, the passive film stability and pitting corrosion resistance decrease obviously. The effect of elastic tensile stress on the inhibition behavior of surfactants for 304 L SS pitting corrosion has the great significance. In this paper, the effect of elast ic tensile stress on inhibition behavior of N -LSS of 304 L SS pitting corrosion has been studied by using various electrochemical tests (Potential polarization (PP), Mott - Schottky test (M -S), electrochemical impedance spectra (EIS) and potential of zero charge (PZC)) and surface characterization tests (Acoustic emission monitoring (AE), scanning electron microscope (SEM), contact angles test (CA), Fourier -transform infrared spectroscopy (F -TIR) and microscopic -infrared imaging (M -IR)). And the exploration of the in fluence mechanism of elastic tensile stress on the inhibition behavior of surfactant for 304 L SS pitting corrosion could provide effective measures and the important theoretical basis of SS pitting corrosion protection for industrial practical application. N-lauroylsarcosine sodium is proved to be effective in inhibiting 304 L SS pitting corrosion. Under various elastic tensile stresses, the inhibition behavior of N -LSS on 304 L SS pitting corrosion is studied, and N -LSS increases significantly 304 L SS pitting potential by more than 400 mV. Under small elastic tensile stress (≤16.63 % σ 0.2), the adsorption of N-LSS can inhibit 304 L SS pitting corrosion by enhancing the protection of N -LSS film and specific adsorption effect of N -LSS. Under large elastic tensile stress (≥46.84% σ 0.2), the decrease of N -LSS adsorption effect reduces the inhibition effect of N -LSS specific adsorption for 304 L SS pitting corrosion growth.

Corrosion inflicts significant financial burdens and poses substantial risks to both safety and the environment [1]. Among the various methods available for corrosion prevention, organic corrosion inhibitors have demonstrated notable effectiveness in safeguarding metallic materials [2 -3]. This study investigates the adsorption mechanism, the process of film formation, and the corrosion inhibition performance of benzotriazole on carbon steels with different grain sizes (i.e., 24.5 μ m, 4.3 μ m, and 0.6 μ m) in 3.5 wt.% NaCl solution. An ultrafine grain of 0.6 μ m exerts a favorable influence on facilitating the creation of a stable and compact corrosion inhibitor film, which resulted in enhanced corrosion resistance and suppressed localized corrosion. These advantageous effects can be attribu ted to the higher adsorption energy at grain boundaries in contrast to grain interiors, expediting the physisorption process and promoting the chemisorption of organic corrosion inhibitors. The investigation comprehensively illustrates, for the first time, the effects of grain size on the adsorption mechanism, film formation process, and inhibition performance of organic corrosion inhibitors on carbon steels. This study demonstrates a promising approach to enhancing corrosion inhibition performance through microstructural design.

The injection of corrosion inhibitors is widely employed as an effective method to mitigate the corrosion rate [1 -3]. The corrosion inhibition performance of inhibitors in the formation water may be affected by factors such as the inhibitor dosing, solubility and shear stress [4-6]. This work focuses on investgating the effect of inhibitor dosing and Cl - content in solution on the 2-mercaptopyrimidine (2-MP) inhibitor film integrity. In this study, the corrosion inhibition efficiency of 2-MP on L360 carbon steel was evaluated using Electrochemical Impedance Spectroscopy (EIS), weight loss measurements, and the adsorption beha vior of 2-MP on an Au surface was explored via Quartz Crystal Microbalance (QCM). All experiments were conducted in CO 2- saturated formation water containing varying concentrations of 2 -MP. Solutions with varying Cl - content were selected to analyze the ion ic influence on the corrosion inhibition behavior of 2 -MP. The inhibition performance of 2 -MP at 20 ppm in CO 2- saturated solutions with varying NaCl contents on L360 carbon steel was assessed through electrochemical, weight loss, and surface analytical methods. The desorption behavior of 2-MP was monitored using QCM and Ultraviolet-Visible Spectroscopy (UV-vis). In addition, molecular dynamics (MD) simulations were employed to investigate the surface adsorption configurations of 2 -MP. The Dynamic Light Scat tering (DLS) technique was used to analyze the changes in micelle size and the diffusion coefficients of desorbed 2-MP molecules in varying NaCl content solutions. The main conclusions are as follows: (1) As 2-MP concentration rises, corrosion inhibition efficiency increases and then stabilizes, peaking at 100ppm due to saturation; (2) As the NaCl content increases, corrosion inhibition performance of 2 -MP declines, and the corrosion rate of L360 carbon steel escalates from 0.0405 mm/a to 0.0914 mm/a; (3) As NaCl content increases, it facilitates 2 -MP desorption on the Au surface, which indicates intensified desorption and promotes the formation of 2-MP micelles.

Carbon dots are an emerging zero dimensional carbon nanomaterial with advantages such as good bio-compatibility and low toxicity. Their nano properties give them excellent surface coverage and anti -corrosion activity, making them a potential green and efficient corrosion inhibitor. This study synthesized boron containing carbon dots (BCDs) with different morphologies using citric acid and boric acid as precursors and hydrothermal synthesis at 150 °C for different durations. BCDs were used as corrosion inhibitors for carbon steel under circulating water conditions, and the influence of carbon dot preparation conditions on their performance as Q235b carbon steel corrosion inhibitors was analyzed. The morphology and structure of BCDs were characterized by Fourier transform infrared spectroscopy, X -ray photoelectron spectroscopy, transmission electron microscopy, and other methods. The corrosion inhibition efficiency of BCDs under circulating water conditions was investigated by weight loss method. In addition, the corrosion inhibition mechanism of BCDs on Q235b carbon steel in circulating water was analyzed by electrochemical impedance spectroscopy, potentiodynamic polarization, and surface analysis techniques. The results indicate that the carbon dots prepared in this study have good corrosion inhibition efficiency on carbon steel in circulating water, and the inhibition efficiency can reach 87% when the BCDs concentration is 200mg/L. This study provides new ideas for the development of green and efficient new corrosion inhibitors.

Conventional corrosion inhibitors often rely on to xic chemicals, raising environmental and health concerns. Consequently, there is a burgeoning interest in developing green corrosion inhibition strategies that are effective and environmentally friendly. Carbon quantum dots (CDs), a novel category of zero -dimensional carbon nanoparticles, having size <10 nm is studied as efficient corrosion inhibitors for various metals. In response to the escalating emphasis on environmental sustainability, researchers have begun utilizing waste materials for CD synthesis, aiming not only to reduce costs but also to mitigate environmental pollution. In this investigation, CDs were synthesized via a hydrothermal method using sugarcane bagasse (biowaste) as the carbon source. The material characterization of the prepared CDs was conducted using Fourier Transform Infra -red spectroscopy (FT -IR), Energy Dispersive Spectroscopy (TEM), X-ray diffraction (XRD), and zeta potential analysis. Further, the corrosion inhibition performance of the resulting CDs on mild steel (MS) in a 5% HCl solution was evaluated through gravimetric measurements, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization curve analysis, spectroscopic and surface analyses. The results unveiled that N,S -doped sugarcane bagasse -CDs exhibited 92% inhibition efficiency at a concentration of 120 mg/L at 35 C after 6h immersion in HCl solution. Further increase in immersion time from 6 hr to 24 hr showed an increase in inhibition performance upto 97% at 120 ppm of CDs. Furthermore, the results of potentiodynamic polarization analysis confirmed that CDs effectively mitigated both the dissolution of the metal at anode and the generation of cathodic hydrogen ions. The adsorption behavior of CDs followed the Langmuir adsorption isotherm. Scanning El ectron Microscopy (SEM)/Energy Dispersive Spectroscopic studies supported the formation of a protective film by CDs onto the metal surface. XPS analysis further confirmed the adsorption of CDs on MS surface.

Carbon dots (CDs) have garnered extensive attention ow ing to their excellent biocompatibility, elevated specific surface area, and facile functionalization, as well as their diverse methods of preparation. In recent times, CDs have been applied for anti-corrosion and obtained some significant results. In this article, the preparation methods of CDs were first briefly introduced, and the relative merits of different approaches highlighted. Subsequently, the application of CDs in the realm of corrosion inhibitors was discussed, and the corrosion inhibition effec ts and mechanism of nitrogen-doped CDs, nitrogen and sulfur-co-doped CDs, as well as CDs functionalized with other elements and nitrogen-co-doped were summarized. Finally, the application of CDs and functionalized CD -modified coatings for anti -corrosion and its protective mechanism was analyzed in detail. This review summarizes recent progress in research related to CDs and heteroatom-doped CDs in anti-corrosion applications and anticipates the prospects and applications of CDs in corrosion protection. With their unique properties and versatile applications, CDs are expected to assume a progressively pivotal role in the advancement of cutting -edge corrosion protection technologies.

Synergistical passive barrier enhancement and active self-healing has been an emerging tactic for developing prominent anti -corrosion coatings. Herein, a cerium/2-methylimidazole metal-organic framework (Ce-MOF) was that is in-situ grown on ultrathin α-ZrP nanosheets with outstanding dispersibility. The parallel arrangement of α-ZrP-based nanosheets within the epoxy matrix was driven by shear for ce from blade-coating technology optimizing the coating's physical barrier and self -repairing capability. This advancement may herald a new era in designing smart coatings and offering potent protection against diverse corrosion types such as filiform corr osion. (word limit 300 words)

Based on the condition of low liquid volume per well and a large amount of wells in the low-permeability oilfields, corrosion/scale prevention for carbon steel tubing and casing need technologies balancing the relationship between economic and technical requirements. A series of technical research and experiments have been applied, including solidification, micro-encapsulation, and downhole controlled release tools for corrosion/scale inhibitors. The experiments were conducted to evaluate the long-term controlled release and corrosion/scale inhibition effect of solid particle corrosion/scale inhibitors u nder different medium and production conditions. After optimization and improvement of formula and processes, a series of long-term corrosion/scale inhibition technologies were developed for different types of oilwells(Table 1) , and 10 related invention patents and 3 standards were obtained, . From 2019 to 2023, this technology system has been applied in more than 2000 wells. By tracking and detecting the residual concentration of chemical agents in the produced fluid, effective period of long effective controlled release inhibitors for single-injection can achieve 3 months, which provides a new economic and technical direction for downhole corrosion/scale protection. The key research directions have been proposed for the subsequent steps: 1. Research on the mechanism and laws of controlled release in solid systems; 2. Simulation and model research on production dynamic release for different types of wells; 3. Products e fficient processing and quality control technology, and multi - functionality; 4. Rapid detection and tracing technology of effective concentration on field; 5. Green compound corrosion/scale inhibitor. Table 1. Technical sequence Types Molding method Applicable wells Scale prediction 1st Solid rod/block Squeezing into Blocks+Tools Low corrosion and scaling wells wells/ year 2nd Solid granular Blended extrusion granulation Jurassic formation wells, 4 times/year wells, t/year 3rd Dispersed soft capsule emulsion polymeriza -tion and film curing Annulus with high pressure wells, injection via pumps, 4 times/year wells, 400 t/a 4th Release control combination tool Solid inhibitors+ controlled release tool <1 time/2 years All kinds of wells

Vapor Phase Corrosion Inhibitors (VPCIs), as an important technology for mitigating atmospheric corrosion, have been increasingly applied in complex and harsh marine atmospheric environments. Vapor phase corrosion inhibitors can continuously volatilize molecules or groups in confined or semi-confined spaces. Owing to their gas permeability and non -interference with the protected objects, they are frequently utilized to prevent atmospheric corrosion of metal components and precision instruments. This review commences with the action mechanism and classification of vapor phase corrosion inhibitors, elaborates on performance analysis methods that include volatility test, corrosion mass -loss test, electrochemical test, adsorption and thermodynamic analysis and microscopic analysis which are applied and improved in researches of corrosion inhibitors. Additionally, it introduces computational simulation techniques for structure -activity relationship. Furthermore, this review discusses the environmental factors affecting the efficacy of vapor phase corrosion inhibitors that include marine salt spray environment, high humidity, alternating temperature and ultraviolet radiation. Finally, this review summarizes research on the synergistic effects, formulation, and molecular modification of vapor phase corrosion inhibitors both domestically and internationally, and aims to encourage a wider use and development of vapor phase corrosion inhibitors by providing further insights into future research in this field.

ToF-SIMS was used to study the adsorption of tetradecyl-benzyl-dimethyl-ammonium (BDA-C14) corrosion inhibitor on carbon steel surface. BDA -C14 forms a protective layer with N -containing polar head group interacting with carbon steel surface. The adsorbed inhibitor surface coverage strongly depends on immersion time and inhibitor concentration. A full and uniform coverage is found for sufficiently long exposure times at a critical inhibitor concentration of about 25 ppmw. For immersion times below 20 min, defective areas remain in the inhibitor layer where iron dissolution with the formation of chloride/hydroxide intermediates occurs. These defective a reas are progressively sealed and a uniform and compact inhibitor layer covers the surface after 1 h of immersion time, mitigates the chloride diffusion through oxide layer and the formation of chloride/hydroxide intermediates.

Plant corrosion inhibitors have advantages over traditional inhibitors, such as being environmentally friendly, abundant in resources, and cost -effective. This study investigates the corrosion inhibition performance of rosemary (Rosmarinus officinalis L.) ethanol extract on steel in a trichloroacetic acid (TCA) solution. A novel inhibitor, ROE, was prepared using ultrasonic extraction, and its corrosion inhibition mechanism on steel in 0.10 mol/L TCA solution was explored through weight loss method, electrochemical methods, surface analysis techniques, and theoretical calculations. The results indicate that at a concentration of 100 mg/L, ROE achieves a corrosion inhibition rate of 96.30% at 20°C. The adsorption of ROE on the steel surface follows the Langmuir isotherm (20 -30 °C ) and the Frumkin isotherm (40 -50 °C ). Electrochemical studies show that ROE acts as a mixed -type inhibitor, with the entire inhibition process controlled by charge transfer, following a "geometric coverage mechanism" accompanied by a "frequency dispersion effect." Surface tests, including AFM, CLSM, and contact angle measurements, indicate that the addition of ROE significantly reduces the corrosion degree and roughness of the steel surface while enhancing its hydrophobicity. Theoretical calculations elucidate the adsorption behavior of ROE on the steel surface and the interactions between ROE and the metal, further confirming that ROE exhibits excellent corrosion inhibition pe rformance by forming an adsorptive film on the steel surface. The research results provide new insights for the high-value utilization of rosemary.

Plant corrosion inhibitors than traditional corrosion inhibitors have th e advantages of low price, green, easy to produce and attracted much attention; this study uses ultrasound-assisted extraction method to prepare a new type of Prinsepia utilis Royle meal extract corrosion inhibitor (PURME), through the weight loss, electrochemical and surface analytical techniques to study the corrosion inhibition of cold rolled steel in sulfuric and hydrochloric acid solutions PURME and the mechanism of action. The results showed that PURME had good corrosion inhibition effect on cold rolled steel in both sulfuric acid and hydrochloric acid, and the corrosion inhibition performance reached 89.25% and 91.28% at 20 oC, respectively. The electrochemical test results show that PURME is a hybrid corrosion inhibitor which mainly inhibits the cathodic reaction, and the whole corrosion inhibition process is controlled by charge transfer, and its corrosion inhibition mechanism is the “geometric coverage effect”. Surface tests show that PURME can reduce the surface roughness and corrosion of steel sheets, and PURME is mainly composed of flavonoids and phenols, which can be adsorbed on the steel surface to form a dense protective film; quantitative calculations were carried out to further illustrate the adsorption behavior of PURME on the surface of the steel and the interactions with the metal surface.

Benzyldimethylstearylammonium chloride (1827) exhibits widespread and potent bactericidal efficacy. However, as a q uaternary ammonium salt cationic surfactant with excellent potential for metal corrosion inhibition has not been unrevealed. Its inhibitory performance and mechanism on cold rolled steel (CRS) in HCl medium was investigated by comprehensive methods. The results show that 1827, serves as a mixed inhibitor, exhibits remarkable surface activity in HCl, efficiently suppressing both cathodic and anodic reactions by occupying active sites, achieving an inhibition efficiency of up to 98.49%. The Langmuir isotherm precisely describes the adsorption behavior of 1827 on the CRS surface. XPS, SEM, and AFM analyses indicate that 1827 effectively adsorbs onto the CRS surface, demonstrating significant inhibitory performance. Theoretical calculations reveal strong interactions between the active moieties of 1827 and the CRS surface, leading to the formation of a protective film through physisorption and chemisorption, effectively impeding the aggressive action of corrosive media. This work provide the basis and theoretical foundation for the application of 1827 in the field of metal corrosion protection.

Aluminum alloy heat exchange tube is attractive for the Low Temperature - Multi Effect Distillation (LT -MED) desalination device, for its low cost and excellent mechanical property. The corrosion dam age is the key issue that influences on its service life. In this work, the corrosion inhibition of the bio -based melatonin (MEL) on AA5052 aluminum alloy in 3wt.% NaCl solution under negative pressure is investigated by the weight-loss method and the elec trochemical measurements. The decrease of the operation pressure makes the corrosion potential of AA5052 aluminum alloy to move positively and decreases its corrosion rate significantly. The corrosion potential and the critical pitting potential shift to t he positive direction in the presence of MEL under different pressure. The MEL inhibits the corrosion of AA5052 aluminum alloy in 3 wt.% NaCl solutions very well. The corrosion inhibition efficiency of MEL decreases evidently under negative pressure. The decrease of pressure can change the surface films of aluminum alloy and thus affects effectively the adsorption behavior of the MEL.

Stainless steel is one of the most widely used metal materials in today's industrial society. However, due to the recent increase in nickel prices, the industry has been prompted to start using low -nickel austenitic stainless steel. Therefore, the substitution of manganese for nickel stainless steel represented by 201 stainless steel (201 SS) has entered people's vision. In the present work, the corrosion inhibitor of 201 SS by cysteine in 1 M HCl is investigated. The corrosion inhibition performance of cysteine at 333 K is investigated by mass loss method and the results show that the corrosion inhibition efficiency of 96.56% is achieved at a concentration of 1.65 mM. The results of potentiodynamic polarization curves show that cysteine is a mixed inhibitor which mainly inhibits the cathodic reaction. It can be observed by SEM that the surface of the steel sheet added with cysteine is smoother than that of the blank, indicating that cysteine can effectively slow down the corrosion of the corrosion medium on the steel sheet. The adsorption of cysteine on the surface of 201 SS conforms to the Langmuir adsorption isothermal model, and the Gibbs free energy of adsorption is -23.45 kJ/mol, which indicating that the adsorption of cysteine on the surface of 201 SS is a mixed adsorption type of physical adsorption and chemical adsorption. The activation energy of the blank group is calculated as 44.19 kJ/mol by the Arrhenius equation, and the activation energy of the reaction increases to 78.66 kJ/mol at a cysteine concentration of 1.65 mM, indicating that the addition of cysteine to the corrosion medium inhibited the metal corrosion reaction. All the above results indicate that cysteine molecules can be effectively adsorbed on the surface of 201 SS and exhibit intentional corrosion inhibition properties.

Agricultural waste of broad bean ( Vicia faba ) stalks extract (VFSE) was prepared in this work. The corrosion inhibition properties of VFSE on cold rolled steel (CRS) in 1.0 M HCl solution were investigated. The result showed that the corrosion inhibition effect of VFSE was significant, and the maximum inhibition efficiency was 90.3% with 100 mg L -1 of VFSE. VFSE adsorption on the CRS surface conformed to the Langmuir adsorption isotherm, and increasing VFSE concentration resulted in higher impedance values. In addition, the surface micromorphology test indicated that VFSE formed an adsor ption film on CRS surface, which effectively retarded HCl corrosion of CRS. TOF-SIMS, XPS and other test results further confirmed the binding of corrosion inhibitor molecules to CRS. The main components of VFSE were determined by LC-MS analysis. Through theoretical calculations, it was found that the active sites of these main components adsorb vigorously to CRS substrates, theoretically confirming the corrosion inhibition effect of VFSE.

Moringa leaves are widely used becau se they are rich in resources and contain a variety of functional components.Moringa oleifera Leaf Extract (MOLE) was obtained by ultrasonic extraction method, and it was used as a corrosion inhibitor in cold rolled steel in 0.10 mol/L NH2SO3H in this study.The corrosion inhibition properties and mechanism of MOLE were evaluated by weight loss method, electrochemical method and surface analysis. The results show that MOLE has good corrosion inhibition performance on cold -rolled steel in NH 2SO3H medium, and t he higher the concentration is, the higher the corrosion inhibition rate is.Feurthermore, MOLE of 0.10 g/L has the best corrosion inhibition performance at 30 °C, at which the corrosion inhibition rate is as high as 91.63%.The adsorption of MOLE on the sur face of cold - rolled steel follows the Langmuir adsorption isothermal formula,and which has the effect of corrosion inhibition through mixed adsorption.Both the corrosion and corrosion inhibition processes are controlled by charge transfer.The addition of M OLE can significantly increase the resistance value of charge transfer, and a dense adsorption film is formed on the surface of CRS, by which the corrosion of CRS by H+ and NH2SO3- is effectively prevented, thus achieving better corrosion inhibition performance.The results of XPS, AFM and contact Angle confirm the existence of effective functional groups in MOLE, which reduces the surface roughness and increases the hydrophobicity of CRS.

Scale adheres to the surfaces of pipelines or cooling water system equipment, impeding heat transfer and accelerating pipeline corrosion. This obstruction not only impacts equipment operation but also leads to s ignificant economic losses. Calcium carbonate (CaCO 3) constitutes the primary component of scale. However, current commercial-scale inhibitors, such as organophosphates, contribute to water pollution. Therefore, the environmentally friendly scale inhibitor polyaspartic acid (PASP) has garnered considerable attention. This study explores three synthetic methods for PASP production: acid -PASP, ammonia -PASP, and alcohol -PASP. Liquid chromatography analysis revealed that alcohol -PASP synthesis produced no by - products. At a dosage of 10 mg/L, the scale inhibition efficiency of alcohol -PASP reached 44%, surpassing that of commercial PASP (10%). The enhanced performance of alcohol-PASP can be attributed to its ability to transform the crystalline phase of CaCO3 from aragonite to a less precipitable form, aragonite, upon introduction.

For mild steel corrosion in industrial production, the rust on the surface of mild steel can be effectively removed by pickling. However, mild steel is often corroded by the pickling agents during the pickling process. The use of corrosion inhibitors can effectively prevent excessive corrosion in the pickling process of mild steel. The corrosion inhibition performance of a mixed syste m of 2 -amino-5-mercapto-1,3,4- thiadiazole (AMTA) and aminothiourea (ATU) for Q235 steel was investigated in 0.5 mol/L citric acid solution in this work. The results showed that the inhibition efficiency (IE) was significantly increased in the presence of t hese two compounds. The IE peaked and the synergistic corrosion inhibition effect became more obvious when the compounding ratio was ATU:AMTA=7:3 and the concentration was 1× 10 -2 mol/L. Furthermore, the result of electrochemical experiment were consistent w ith that of weight loss measurements. For citric acid solutions with a compound inhibitor of constant concentration and volume ratio, the corrosion inhibition efficiency demonstrated a decline with an increase in temperature. Figure.1 (a)Potent iodynamic polarization curve of MS in citric acid medium with different volume ratios of composite corrosion inhibitors of equal concentration;(b) Potentiodynamic polarization curve of MS in citric acid medium with mixed corrosion inhibitors of equal proportions and concentrations

Industrial waste has complex and diverse compositions, this implies that during the prolonged operation of a waste incineration boiler, the corrosiveness of the alkali chloride slag layer, which accumulates on the high-temperature heating surface material and condenses locally, may poses a threat to the safe operation of the equipment. The influence of slag layer formation during industrial waste incineration on the high -temperature corrosion behavior of 20G steel used in incinerators was investigated, as well as the effects of different additives. The experimental results show that the slag layer exacerbates the high-temperature corrosion behavior of carbon steel at 500 °C, and the coarse -grained slag layer has a certain protective effect on the carbon steel as the temperature rises (after 700 °C).The addition of alumina and vermiculite at 500°C can effectively inhibit the corrosion of the slag layer on the carbon steel of 20G, while the dolomite and kaolin promote the corrosion of the carbon steel. After 10% of alumina was added, the corrosion rate of the slag generated by industrial incineration combustion on 20G carbon steel was reduced by 23%. At 500°C, the high-temperature corrosion process of the slag layer was dominated by salts such as NaCl and Na2SO4, chloride salts accelerate the destruction of the oxide layer on the surface of the metal, and SO2 and SO3 produced by the dissociation of sulfate salts can easily penetrate the oxide layer, leading to further corrosion of the metal. After the addition of alumina reduced the cracking of the corrosion layer on the surface of the carbon steel and increased the oxide film protective layer, thus reducing the metal corrosion caused by the slag layer.

The high -temperature corrosion characteristics of 20G st eel in industrial incineration ash were studied through weight gain experiments, response surface analysis and Material stuido simulation, and the corrosion inhibition mechanism of alumina particles was investigated. The results show that the corrosion weight gain of industrial incineration ash on metal changes with time in a parabolic pattern, and the corrosion weight gain gradually decreases after adding alumina. Alumina promoted the formation of high melting point minerals such as Ca 2Al2SiO7 and Al2SiO5 in industrial incineration ash. Response surface results showed that the interaction of experimental temperature and corrosion time had the greatest effect on the weight gain of metal corrosion. At the same temperature, the binding energy between NaCl and alumina is significantly larger than that between NaCl and Fe. Strong chemical interactions between Na +, Cl-and alumina were obtained by RDF radial function calculations. At the same temperature, the diffusion coefficients of Na + and Cl - on the surface of alumina were larger than those on the surface of Fe. NaCl was more likely to bind to the alumina than to the metal surface, thus alleviating the corrosion of metals by industrial incineration ash.

过渡金属碳(氮)化物( MXene)是第一种兼具亲水性和导电性的二维材料, 具有优异的力学性能、可调的表面官能团、光电(热)效应等性能而成为近期的研究 热点[1]。湿法刻蚀目前最常用的“自上而下”从 MAX 前驱体制备 MXene 的方法;但刻蚀 使用的 HF 酸或 HCl 配合 LiF 不可避免的造成 MXene 产物出现基面缺陷,再加之二维 片层必然存在的边缘,成为 MXene 氧化敏感位点。更不幸的是溶剂水即可视作氧化 MXene 的腐蚀性介质,氧化生成金属氧化物与无定形碳,完全丧失其优异的理化性能。 据报道,优化 MAX 相结构、温和刻蚀、调节存储环境、表面修饰和添加抗氧化剂等措 施可 MXene 氧化。其中,添加抗氧化剂具有操作简单、成本低且高效等优点,是减缓 MXene 氧化的有效方法。抗坏血酸钠、聚阴离子盐、单宁酸、离子液体等化合物均被 证明可提高 MXene 的化学稳定性[2]。但上述抗氧化剂仍存在用量大,抗氧化机理不明 等问题。 据此,本文根据 “缓蚀”理论与研究方法,分别构建了酒石酸钠( ST)对 Ti2CTx-MXene 以及 Ti3C2Tx-MXene 的抗氧化体系;借助色差法追踪 MXene 的氧化历程,当 ST 在最佳添加浓度为 0.3 mg/mL 时,ST-MX(Ti2)和 ST-MX(Ti3)的时间常数分别 可达到 565.5 小时和 239.3 天;通过形貌、XPS、pH 与温度加速实验以及电化学性能 测试来表征 ST 的抗氧化效果;结果表明,老化 96 小时后,0.3ST-MX(Ti2)依旧保持 层状结构,代表 Ti–C 主链的贡献比仍然明显,并且其电容值仍有 262.8 F/g,在恶劣环 境(pH 为 2.5,温度为 80°C)下的时间常数仍可分别达到 5.9 和 7.4 小时;采用多尺 度理论计算,阐明 ST 稳定 MXene 的机理,发现 ST-在 MXene 表面的吸附倾向于边缘 和缺陷的覆盖,从而减缓氧化的进展。本研究提供了一种可有效延长 Ti 基 MXene 的可 行途径,并且采用该抗氧化措施后,MXene 依然保留优异的抗氧化性能。 图 1 ST 稳定 MXene 过程示意图

To enhance corrosion resistance and extend the service life of coatings, layered double hydroxides (LDH) have been embedded into coatings to create a hybrid of organic -inorganic micro/nano -containers, improving the coatings' physical barrier properties. Herein, an elaborately designed strategy is proposed to in -situ grow LDH on nanofibers, thereby obtaining polyvinylidene difluoride/hydrotalcite@deprotonated benzotriazole (PVDF/LDH@BTA −) composite nanofibers, followed by incorporation into an epoxy resin to formulate the composite coating. The even distribution of LDH within the coating, aided by nanofibers, significantly bolstered the coating's barrier effect. Upon exposure to corrosiv e environments, the hydrotalcite structure within PVDF/LDH@BTA− adsorbs chloride ions through anion exchange, capturing up to 0.26 mmol/cm2 of chloride ions. Concurrently, corrosion inhibitors were released, forming a protective layer on the copper surface to substantially mitigate the corrosion process. This innovative approach markedly enhances the composite coating's long -term corrosion resistance.

Corrosion is the primary cause of material degradation in industrial applications[1]. The application of corrosion inhibitors [2] is essential in preventing and mitigating the corrosion of metal c omponents. Nevertheless, to select and design corrosion inhibitors suitable for specific materials and environments, researchers often rely on time-consuming laboratory experiments and gradually modify the structures of existing inhibitors [3]. Material che mists expect to identify the critical chemical substructures that affect corrosion inhibition performance to gain actionable insights, such as hints for inhibitors’ structural optimization. With the rapid development of artificial intelligence (AI) technology, deep learning models have attracted attention for their exceptional feature extraction and representation capabilities, particularly in domains involving graph -structured data [4]. Molecules, composed of atoms connected by chemical bonds, can be natur ally represented as graphs, with atoms as nodes and bonds as edges[5]. The integration of deep graph learning into materials science may expedite the process of selecting and designing corrosion inhibitors. This study proposes a graph interpretation -based substructure mining method and constructs a graph neural network (GNN) model [6] to predict the inhibition efficiency (IE) of molecules. Fig.1 illustrates the overall framework of our model. Our model integrates multi -scale features and identifies critical substructures that significantly impact IEs. The model highlights the chemical substructures responsible for high IEs and provides a chemistry -intuitive explanation of structure-property relationships, facilitating rapid and precise IE predictions. The results demonstrate that GNN-based models outperform traditional machine learning methods in prediction accuracy and computational efficiency, with a 7% RMSE. The models are poised to become reliable tools for selecting and optimizing inhibitors. Compared t o traditional methods that rely on intuition or experience, the data-driven graph interpretation method assists chemists in identifying chemical substructures with corrosion inhibition properties, guiding the design of effective new corrosion inhibitors. Fig.1 Overall Framework of IE Prediction Model based on Substructure Mining.

Machine learning algorithms are advancing material research into a fourth paradigm[1]. However, their application in mater ial science faces significant hurdles, including the expensive acquisition of high -quality data and data scarcity[2]. The introduction of prior knowledge can mitigate these limitations, but the scattered and unstructured nature of material science publicat ions complicates knowledge aggregation. This issue is especially acute in the study of multi-principal element alloys (MPEA)[3], where the complexity of their compositions and structures complicates performance predictions[4]. Efficiently collecting materi al knowledge and data and incorporating complex interactions within machine learning models to enable new material discoveries presents a significant scientific challenge. Fig 1. Knowledge and Data-driven Framework for Multi-Principal Element Alloys To address the aforementioned issues, we propose a knowledge and data -driven framework (Fig 1) to explore MPEA, integrating automated knowledge acquisition, representation, and rediscovery. Initially, we established an automated extraction pipeline based on ChatGPT, guided by material experts, to extract component, property data, and information on processes and structures from MPEA literature, addressing data dispersion and building a diverse dataset of alloy hardness and corrosion. Subsequently, we proposed a cross -modal material property prediction model, Mat -NRKG, that utilizes a cross -modal knowledge graph to integrate experimental data and process information, achieving high -precision performance predictions of MPEA, exceeding the baseline by 18.5% and 13.7% on MSE metrics in hardness and corrosion resistance predictions, respectively. This method enables precise analysis of complex material property using small, real-world datasets. Finally, using the Mat -NRKG model, we performed high -throughput predicti ons, expediting knowledge discovery via SHAP[5], spatial mapping, and visualization techniques. Through the "acquisition -integration-utilization-discovery" process, we seamlessly integrate knowledge and data, fully utilizing existing experimental results t o deepen our understanding of material performance. This framework not only improves our comprehension of material properties but also expands opportunities for knowledge - driven research in material science, showing significant application potential.

At present, atmospheric corrosion research mainly relies on coupons specimen, which usually generate data once a year [1]. In contrast, at mospheric corrosion monitoring (ACM) technology can reflect the corrosion rate in real time through current [2]. However, it is expensive and difficult to deploy sites over a large area like coupon experiments. Building corrosion maps based on data from a f ew monitoring stations is a challenging problem. However, the development of artificial intelligence technology has provided new possibilities for solving this problem. A complex nonlinear relationship between corrosion current and environment is establis hed through a deep network [3], and the corresponding corrosion current is predicted based on the environmental variables of unmonitored locations, thereby helping to analyze the changes in corrosion rate over time and space. However, there are few ACM moni toring sites. In order to enable the neural network to effectively fit the relationship between environmental variables and corrosion currents at different locations, this paper proposes a knowledge embedding neural network (KENN) model for the prediction of atmospheric corrosion rates. Figure 1 shows the overall framework of our model. The model embeds common corrosion knowledge into the neural network, which compensates for the sparsity of monitoring sites and ensures that the prediction results are consistent with the prior knowledge[4]. The data simulation results show that KENN outperform other traditional machine learning methods in terms of prediction accuracy. Additionally, there is good agreement between the corrosion maps built from ACM data and t hose built from coupon data within one year. According to actual needs, the data obtained through KENN can be used to build corrosion maps for any time period, which can help researchers better understand the spatial and temporal variations of atmospheric corrosion. Fig.1 Overall Framework for Corrosion Rate Prediction based on KENN.

Electrons and phonons are regarded as the microscopic carriers of friction energy dissipation and their coupling is a typical dissipation mode. However, due to the lack of ultrafast detection technic, the friction mechani sm about electron -phonon coupling remains unexplained. Here, using high resolution non -contact atomic force microscopy and femtosecond transient absorption spectroscopy, we find that interlayer electron-phonon coupling dissipation channel in WS 2/graphene heterostructures can be opened by defects. This is because defects provide a recoil -momentum which satisfies the requirement of momentum conservation between electrons in WS 2 and acoustic phonons in graphene and interlayer electron -phonon coupling occurs. Besides, the electron-phonon scattering time is accelerated from 2.4 ps to 1.1 ps. The enhanced electron-phonon coupling leads to significant energy dissipation. We further quantitatively model the friction with dissipation rate as to control the friction energy dissipation by ultrafast interlayer electron -phonon coupling. This work provides a new way to understand the mechanism of electron -phonon coupling in friction.

Conducting polymers were widely used as filler or coating to protect metal components against corrosion. One of the interesting points is that the reduction of the conducting polymer to release counterions ( Where the counterions are the anionic corrosion inhibitors) and then transport to the defect sites to provide active corrosion protection. However, an interesting question is when the released corrosion inhibitor or counterions fail to reach the critical concentration or are unable to effectively migrate to the corrosive sites, thereby hindering self-healing at the damaged areas. To realize high corrosion inhibitor loading capacity and effective transportation, a strategy termed 'first transport, then entra p' was proposed. In this approach, the transportation properties of the corrosion inhibitors are first investigated, followed by designing the entrapment of the corrosion inhibitor into the coating matrix. Our findings suggest that this strategy has great potential for designing smart coatings based on micro/nano container.

The rapid advancement of Industrial Internet of Things (IIoT) and machine learning technologies has exposed limitations in traditional corrosion risk assessment methods, particularly in terms of accuracy and real -time performance. This study presents an innovative machine learning -based framework for corrosion risk assessment in long-distance pipelines. The framework integrates public environmental factors (e.g., meteorological and geological data) with private operation and maintenance data (e.g., intel ligent pigging and cathodic protection monitoring data). For data management, customized preprocessing workflows have been designed for various data types, and information is organized in an N -dimensional vector format to ensure data quality and consistenc y. The modeling component employs an adaptive optimization algorithm based on historical data, incorporating multiple pre-set machine learning models and their hyperparameter spaces. Through automatic adjustment and selection of optimal model configuration s, the framework significantly improves the accuracy and generalization capability of risk assessment. Multiple specialized models are coupled using ensemble learning methods, forming an end-to-end risk assessment workflow. This study also explores strateg ies for model deployment and continuous optimization mechanisms, ensuring the framework's scalability and maintainability in practical production environments. The proposed comprehensive framework aims to enhance the accuracy, efficiency, and adaptability of corrosion risk assessment for long-distance pipelines, thereby providing robust support for operation and maintenance decisions.

Magnesium alloys as the lightest engineering metals have the potential to be widely used in transportation etc, but the bad corrosion resistance has limited the further applications. To overcome the limitations of traditional experimental trial -and-error approach in corrosion research, the ab -initio method to predict the polarization curves for galvanic corrosion of multi -phase Mg alloys has been established. To accelerate the screening of Mg alloy systems with better corrosion resistance, the corrosion materials genome have been further developed by combining the high - throughput-simulations and machine learning methods. The important surface atomic features have been also uncovered in terms of reducing the cathodic hydrogen evolution and anodic Mg dissolution kinetics, which have successfully guide d the experimental development of corrosion-resistant Mg alloys.

This study explores how hydrogen bo nding at electrochemical interfaces influences corrosion processes. While hydrogen bonds have recently been recognized for their role in electrocatalytic selectivity and hydrogen transfer, their impact on charge transfer at corrosion interfaces has not bee n thoroughly investigated. Our findings demonstrate that the hydrogen bonding network on metal surfaces significantly affects the corrosion process at atomic and electronic levels, highlighting how these bonds act as pathways for electron transfer. This insight offers a deeper understanding of the role of hydrogen bonding in corrosion electrochemistry. Building on this, our previous work provided detailed hydrogen bond characterization 1and introduced quantitative indicators for assessing hydrogen bonds 2.Additionally, we examine the effects of key sulfides—hydrogen sulfide (H 2S), carbonyl sulfide (COS), and dimethyl sulfide (DMS)—on the stability of titanium oxide passive films in seawater. Through density functional theory (DFT) and ab initio molecular dynam ics (AIMD), we analyze the adsorption and surface electronic properties of these sulfides on the anatase TiO2(101) surface. The optimal adsorption configurations for H2S, COS,and DMS on the anatase TiO2(101) surface are 2O b-vertical, O-down-vertical, and O b-parallel, with adsorption energies of -1.32, -0.67, and -1.86 eV, respectively. Through comparative AIMD simulationsof three different aqueous solutions on the TiO 2(101) surface, we have observed that COS exerts a more pronounced influence on the electrical double layer within 3.00 Å of the TiO2(101) surface. Specifically, the hydrogen atoms of water tend to aggregate towards the O b atoms, forming hydrogen bonds, which significantly impacts the corrosion resistance of the TiO2 surface.

Petrochemical industry is the pillar industry of modern industry in China. As the leading device of petroleum refining industry, the equipment integrity of atmospheric distillation unit is of great significance to the safe and stable operation of subsequent process. China's crude oil resources are in short supply, and crude oil imports are large. The processing of low -quality crude oil such as high sulfur, high nitrogen, high acid and chlorine has become the development trend of the industry. As the first production process in the petroleum refining process, the atmospheric and vacuum distillation unit is affected by the processing of inferior crude oil, and the corrosion failure cases in t he unit are frequent, which affects the economic benefits and the life safety of the production personnel. The types of corrosion failure in the atmospheric tower are complex, and it is difficult to form an effective corrosion prediction method. For the co rrosion mechanism of the low temperature part of the atmospheric tower top system, such as the prediction and protection of ammonium salt corrosion and dew point corrosion, it has become the focus of research. In this paper, the risk prediction and corrosion mechanism of ammonium salt corrosion and dew point corrosion at the top of atmospheric tower are studied. The failure evolution law based on flow corrosion and the corrosion protection measures and intelligent prevention and control measures of the over head system of atmospheric tower are introduced. The diagnosis process and prevention and control measures for identifying the risk of flow corrosion are proposed. It provides theoretical guidance for the study of crystallization corrosion mechanism and de w point corrosion mechanism of low temperature ammonium salt at the top of atmospheric tower and the prediction of intelligent corrosion protection.

Designing environment-friendly, high-efficiency, and low-toxicity copper (Cu) corrosion inhibitors is an important topic in the field of corrosion inhibitors. The current design of organic corrosion inhibitors ma inly depends on empirical trial -and-error approaches. New methods are needed to accelerate and rationalize the design of corrosion inhibitors. The possible correlation between standard adsorption Gibbs energy and inhibition efficiency provides an opportuni ty for the rational design of corrosion inhibitors. A high -throughput computational framework is established for automatic computation of adsorption energies of organic corrosion inhibitors. A correlation between adsorption energies and changed Cu -d band centers induced by molecular adsorption is established. Standard adsorption Gibbs energies were derived based on additional thermodynamical and solvation correction. Standard adsorption Gibbs energy cannot be directly correlated with the inhibition efficiency. While some of corrosion inhibitors show linear correlation with standard adsorption Gibbs energies and inhibition efficiencies, the rest do not due to their orientation-dependent adsorption mechanisms.

The protection and maintenance of material corrosion have always been a significant part of the national economy, and evaluating the corrosion performance of materials has always be en a laborious task. Due to corrosion in different service environments, materials will exhibit different corrosion phenomena and mechanisms, which poses great challenges to the evaluation of their corrosion performance. At present, most evaluation methods are based on monitoring and testing data for analysis and evaluation, lacking a material corrosion service performance evaluation method that can truly combine monitoring data with real -time correction and evolutionary reasoning of material corrosion mechanism models. Digital twin technology provides a method for evaluating the corrosion service performance of materials, which includes establishing a corrosion data sensing system and constructing a corrosion information database. Using online environmenta l data and reprocessing data from multiple materials as inputs for the corrosion intelligent digital mechanism model, this technology provides life prediction for the corrosion performance of service materials and achieves digital twin of material corrosion service performance. This work takes the evaluation of the corrosion service performance of aluminum alloys as an example.

The marine environment of ocean engineering projects is harsh, and the application of traditional cathodic protection equipment in ocean engineering faces problems such as high maintenance costs, untimely parameter adjustment, low work efficiency, and large errors. In response to the existing corrosion control demands of ocean engineering, this article takes the intelligent control system project for cathodic protection of jacket structures in an offshore step -up station as a demonstration, proposes an intelligent control and regulation scheme for cathodic protection. It elaborates on the design and implementation process of the cathodic protection intelligent control system, including system component selection, layout design, numerical simulation verification, and on-site testing and effect evaluation of intelligent control, aiming to promote the application and development of cathodic protection intelligent control in the field of ocean engineering.

With the development of artificial intelligence, AI -assisted detection can improve safety, reduce costs, provide objective classification, and integrate with digital asset management systems. Therefore, corrosion assessment using image segmentation technology has become a research direction that has attracted much attention. Deep learning methods have advant ages in strong learning ability, adaptability to complex scenarios, end -to-end training, and strong transferability, and are suitable for processing complex corrosion images of WS. Traditional methods have advantages in high computational efficiency, stron g interpretability, friendliness to small sample data, and easy deployment, and are suitable for scenarios with high real-time requirements and low data volume. At present, most of the existing corrosion research based on image recognition focuses on identifying and calculating local corrosion areas, and the detection targets are mainly limited to locating and quantifying corrosion areas. Modeling and analysis of uniform corrosion and surface rust evolution of WS are still rare. Therefore, in this study, a large amount of corrosion image data was quickly collected through dry -wet cycle experiments, and the corrosion surface of weathering steel was simulated and modeled by combining image segmentation with machine learning. The model interpretability was veri fied and enhanced through a series of microstructural characterizations, providing new directions and promising results for the prediction and non-destructive monitoring of atmospheric corrosion of weathering steel. Figure 1. Schematic diagram of model calculation results of corrosion image Figure 2. Example of model calculation of outdoor WS bridge corrosion image

As the navigation area of ships becomes wider and the requirements for long-term use and functionality become higher, traditional anti-corrosion and anti-fouling coatings are unable to meet the future development needs of ships. This lecture will focus on the long-term anti-fouling needs of oceangoing vessels and the anti -cavitation corrosion needs of ship propellers. It will introduce the research progress of temperature - sensitive intelligen t anti -fouling coatings, high -strength targeted self -healing anti - cavitation anti-corrosion coatings, and other intelligent anti -corrosion and anti -fouling technologies from the aspects of coating function design, resin structure design, formula design, and actual sea evaluation. It will explore the development direction of future anti-corrosion and anti-fouling coatings and provide reference for the design of anti-corrosion and anti-fouling schemes for future ships.

With the development of oil and gas field construction in the directions of digitalization and intelligence, the cor rosion control in oil and gas field construction projects has gradually achieved digital and intelligent development through digital design, digital delivery, and intelligent monitoring. The corrosion control technology, is integrated the model information introduced by a 3D design and the material coding with the 3D model, constitutes a digital life entity of corrosion control. In the procurement stage, the precise information carried by the digital object is transferred to the procurement process, laying a foundation for precise and efficient procurement. In the construction stage, the digital object with detailed information facilitates organizations, controls, installations, and more information collection. In the operation and maintenance stage, after t he plant is completed and put into production, the digital object carrying the design, procurement, construction, and other information is aggregated into the digital twins of the plant during the operation and maintenance period. The digital life entity is further endowed with mathematical models and intelligent applications. The corrosion monitoring parameters are regularly detected and uploaded in real time, providing guidance for corrosion control operation and maintenance. The refined digital delivery of corrosion control provides basic information for procurement, construction, operation and maintenance, and full life cycle management. It offers strong support for the realization of the digital and intelligent development of corrosion control in oil an d gas fields.

Magnesium alloys as the lightest engineering metals have the potential to be widely used in transportation etc, but the bad corrosion resistance has limited the further applications. To overcome the limitations of traditional experimental trial-and-error approach in corrosion research, the ab-initio method to predict the polarization curves for galvanic corrosion of multi -phase Mg alloys has been established. To accelerate the screening of Mg alloy systems with better corrosion resistance, the corrosion materials genome have been further developed by combining the high -throughput-simulations and machine learning methods. The important surface atomic features have been also uncovered in terms of reducing the cathodic hydrogen evolution and anodic Mg dissolution kinetics, which have successfully guided the experimental development of corrosion-resistant Mg alloys.

Lithium metal negative electrode cause the generation and accumulation of dead lithium due to unstable SEI film, dendrite growth, and interface corrosion, which seriously deteriorate s battery performance and life. Lithium corrosion involves chemical and e lectrochemical corrosion, resulting in rapid loss of battery active substances, and substantial attenuation of battery performance and life. Through cryo-electron microscopy and three -electrode electrochemical technology, the corrosion science of the batte ry was deeply analyzed. T he effective strategy of passivation protection of the negative electrode by organic/inorganic composite coating was proposed. The corrosion inhibition rate reached 74%, and the battery cycle life was increased several times. Fig. 1 金属锂负极失效调控

The rapid advancement of Industrial Internet of Things (IIoT) and machine learning technologies has exposed limitations in traditional corrosion risk assessment methods, particularly in terms of accuracy and real -time performance. This study presents an innovative machine learning-based framework for corrosion risk assessment in long - distance pipeli nes. The framework integrates public environmental factors (e.g., meteorological and geological data) with private operation and maintenance data (e.g., intelligent pigging and cathodic protection monitoring data). For data management, customized preprocessing workflows have been designed for various data types, and information is organized in an N-dimensional vector format to ensure data quality and consistency. The modeling component employs an adaptive optimization algorithm based on historical data, inc orporating multiple pre-set machine learning models and their hyperparameter spaces. Through automatic adjustment and selection of optimal model configurations, the framework significantly improves the accuracy and generalization capability of risk assessm ent. Multiple specialized models are coupled using ensemble learning methods, forming an end -to-end risk assessment workflow. This study also explores strategies for model deployment and continuous optimization mechanisms, ensuring the framework's scalabil ity and maintainability in practical production environments. The proposed comprehensive framework aims to enhance the accuracy, efficiency, and adaptability of corrosion risk assessment for long - distance pipelines, thereby providing robust support for ope ration and maintenance decisions.

Designing environment -friendly, high -efficiency, and low -toxicity copper (Cu) corrosion inhibitors is an important topic in the field of corrosion inhibitors. The current design of organic corrosion inhibitors mainly depends on empirical trial -and-error approaches. New methods are needed to accelerate and rationalize the design of corrosion inhibitors. The possible correlation between standard adsorption Gibbs energy and inhibition efficiency provides an opportunity for the rational design of corrosion inh ibitors. A high -throughput computational framework is established for automatic computation of adsorption energies of organic corrosion inhibitors. A correlation between adsorption energies and changed Cu -d band centers induced by molecular adsorption is established. Standard adsorption Gibbs energies were derived based on additional thermodynamical and solvation correction. Standard adsorption Gibbs energy cannot be directly correlated with the inhibition efficiency. While some of corrosion inhibitors show linear correlation with standard adsorption Gibbs energies and inhibition efficiencies, the rest do not due to their orientation-dependent adsorption mechanisms.

The HHSAMed 5A06 deposition, fabricated via hybrid heat-source solid-state additive manufacturing (HHSAM), exhibits a more homogeneous microstructure with elevate d microhardness (89.9 HV0.5), yield strength (238.3/184.0 MPa), ultimate tensile strength (358.1/324.5 MPa) and elongation of 27.5%/15.7%, respectively. The heat - source enhances the material flow behavior and the interlayer bonding strength among the stack ing layers, excluding the effects of grain refinement and precipitate strengthening. It demonstrates superior corrosion resistance relative to the AFSD deposition and 5A06 feedstock, attributed to the most stable passive film, a greater concentration of Al6(Fe,Mn) and the lack of Al3Mg2.

Corrosion Under Insulation (CUI) is a major problem for process industry operators, accounting for up to 10% of overall maintenance costs. One of the key challenges is the hidden nature of the problem due to the presence of the insulation and cladding layers preventing access to the equipment surface during normal operation. Other challenges include a lack of available data regarding the CUI environmen t itself, as well as accurate and reproducible methods to determine the condition of the substrate, protective coating and insulation without removal of the external cladding. Recent breakthroughs in Electrochemical Impedance Spectroscopy (EIS) based senso r technology has enabled the development of onsite monitoring systems which can provide advance warning of coating breakdown. This in turn creates the possibility for just-in-time maintenance to mitigate or prevent CUI, delivering cost savings in maintenance and operations.

An ideal microcapsule effectively preserves active molecules and can rapidly release it to elicit a self-healing anticorrosion function. However, the development of highly efficient microcapsules remains a great challenge. Herein, polymer/metal-organic framework hybrid microcapsules with dynamic properties were constructed as self-healing anticorrosion coatings. The shell of the microcapsule consisted of flexible polydopamine and a hard crystalline zeolitic imidazolate framework-8 layer. The corrosion inhibitor 8-hydroxyquinoline was trapped in the microcapsules and remained unreleased because the ZIF-8 layer acted as a molecular sieve. When the coating was surrounded by an acidic environment, the ZIF-8 nanocrystals in the shell dissociated, followed by the release of corrosion inhibitor. A dense protective layer was formed on the steel surface to suppress extensive corrosion propagation. In contrast to conventional coatings, the novel dynamic hybrid microcapsules enable the application of self-healing coatings that can withstand harsh acidic environments without human intervention.

Temperature, CO2 partial pressure, Cl-concentration, cathodic protection potential, etc. will all affect the growth and corrosion behavio r of SRB. Through weightlessness corrosion testing, electrochemical testing and 16S rRNA gene sequencing, the change in the quantity of SRB and the corrosion characteristics of materials in a simulated field environment were studied. The corrosion rate and life were predicted by monitoring the electrochemical characteristics of the material surface to ensure timely alarm in complex service environments to reduce the occurrence of corrosion failure accidents.

High-throughput experimental techniques can accelerate and economize corrosion evaluation, and thus, have great potential in the development of new materials for corrosion protection such as corrosion-resistant metals, corrosion inhibitors, and anticorrosion coatings. In this work, a novel high-throughput screening method of the stabilization treatment agents for promoting the growth of rust layers on weathering steel surface is developed by depositing microarrays of droplets containing different stabilizer solutions on a Q420 MPa low-alloy weathering steel. This method can test up to 200 channels of stabilizer solutions with a miniaturized setup. In addition, the method allows the independent control of droplet compositions and concentrations. Different combinations and concentrations of Na2WO4, Na2MoO4, and NaNO2 were dropped on the steel surface, and the growth behavior of the rust layer and the corrosion resistant property were assessed using the wire beam electrode (WBE) technology and surface observations. The combination of 0.6 g/L Na2WO4 and 1.2 g/L Na2MoO4 could promote the generation of a dense rust layer with a high percentage of α-FeOOH, which is conductive to strengthen the corrosion resistant property of the rust layer. WBE electrochemical results demonstrate the highest impedance modulus among all the stabilizer combinations. Figure. (a) Photograph of rust layers on Q420 weathering steel with Na2WO4 and Na2MoO4 addition; (b) 0.01 Hz impedance modulus measured on each wire beam electrode.

Electrons and phonons are regarded as the microscopic carriers of friction energy dissipation and their coupling is a typical dissipation mode. However, due to the lack of ultrafast detection technic, the friction mech anism about electron-phonon coupling remains unexplained. Here, using high resolution non-contact atomic force microscopy and femtosecond transient absorption spectroscopy, we find that interlayer electron - phonon coupling dissipation channel in WS2/graphen e heterostructures can be opened by defects. This is because defects provide a recoil-momentum which satisfies the requirement of momentum conservation between electrons in WS2 and acoustic phonons in graphene and interlayer electron -phonon coupling occurs. Besides, the electron-phonon scattering time is accelerated from 2.4 ps to 1.1 ps. The enhanced electron-phonon coupling leads to significant energy dissipation. We further quantitatively model the friction Γ with dissipation rate τ−1 as Γ = 2.75 × 10−17 τ−1 to control the friction energy dissipation by ultrafast interlayer electron -phonon coupling. This work provides a new way to understand the mechanism of electron -phonon coupling in friction.

Lithium salts have been intensively investigated as a viable alternative in the development of environmentally friendly and sustainable corrosion inhibitors for the corrosion protection of aerospace aluminum alloys. Lithium ions are crucial in stabilizing the reaction products, leading to the formation of a protective multilayer structure. Prior studies have focused on studying the corrosion protection of the protective layer using traditional e lectrochemical methods. However, local electrochemical characteristics of its final spatially resolved protective behavior upon exposure to corrosive conditions were yet unknown. Using Scanning Electrochemical Microscopy (SECM) and electrochemical noise (EN) measurements, complemented by FIB-SEM analysis, it was found that areas around intermetallic phases (IMPs) represented weak spots due to an insufficient generation of a protective inner dense layer. For the freshly formed conversion layer, both the top and the inner layer underwent a gradual dissolution upon exposure to a relatively dilute NaCl solution within 2 h due to their chemical instability. For the ambiently -aged conversion layer, most corrosion activity around IMPs was related to the S-phase and large constituent phases, due to their intrinsic electrochemical instability and inherently lower local conversion layer quality, respectively. Moreover, S-phase-related corrosion activity lasted approximately 8 h due to fast dealloying, whereas reaction s induced by large constituent particles remained active over the entire re-immersion period of 12 h.

Machine learning algorithms are advancing material research into a fourth paradigm. However, their application in material science faces significant hurdles, including the expensive acquisition of high-quality data and data scarcity. The introduction of prior knowledge can mitigate these limitations, but the scattered and unstructured nature of material science publications complicates knowledge aggregation. This issue is especially acute in the study of multi-principal element alloys (MPEA), where the complexity of their compositions and structures complicates performance predictions. Efficiently collecting material knowledge and data and incorporating complex interactions within machine learning models to enable new material discoveries presents a significant scientific challenge. Fig 1 Knowledge and Data-driven Framework for Multi-Principal Element Alloys To address the aforementioned issues, w e propose a knowledge and data -driven framework (Fig 1 ) to explore MPEA, integrating automated know ledge acquisition, representation, and rediscovery. Initially, we established an automated extraction pipeline based on ChatGPT, guided by material experts, to extract component, property data, and information on processes and structures from MPEA literature, addressing data dispersion and building a diverse dataset of alloy hardness and corrosion. Subsequently, we proposed a cross -modal material property prediction model, Mat -NRKG, that utilizes a cross -modal knowledge graph to integrate experimental data and process information, achieving high -precision performance predictions of MPEA, exceeding the baseline by 18.5% and 13.7% on MSE metrics in hardness and corrosion resistance predictions, respectively. This method enables precise analysis of complex material property using small, real-world datasets. Finally, using the Mat -NRKG model, we performed high -throughput predictions, expediting knowledge discovery via SHAP, spatial mapping, and visualization techniques. Through the "acquisition -integration-utilization-discovery" process, we seamlessly integrate knowledge and data, fully utilizing existing experimental results to deepen our understanding of material performance. This framework not only improves our comprehension of material properties but also exp ands opportunities for knowledge - driven research in material science, showing significant application potential.

锂金属负极由于不稳定的SEI膜,枝晶生长,界面腐蚀等原因造成死锂的产生和积 累,严重恶化电池性能和寿命。锂腐蚀涉及化学和电化学腐蚀,导致电池活性物质迅 速损失,电池性能和寿命大幅衰减。通过冷冻电镜和三电极电化学技术深入剖析电池 中的腐蚀科学,并提出有机/无机复合涂层钝化保护负极的高效策略,腐蚀抑制率达 74%,电池循环寿命提升数倍。 Fig. 1 金属锂负极失效调控

Electric power is the signi ficant support of national economy. However, large steel structures of the power stations in coastal areas are facing harsh atmospheric corrosion conditions in long term. It may decrease the reliability of devices and brings high safety risks. As one commo nly used maintenance method, manual inspection is time-consuming, labor -intensive, and poses severe personal safety risks. The advancement of computer vision techniques offers a rapid and accurate non -contact alternative for detecting corrosion in such str uctures. In this paper, we addressed the limitations of existing deep learning methods for accurate detection of corrosion from the interference such as aged coating yellowing by proposing an improved YOLOv8n model, YOLOv8 -RM. The method enhanced the extra ction of corrosion features in complex backgrounds by incorporating the RepNCSPELAN4 module and the MC attention mechanism module, leading to improved detection accuracy. Comparative experiments demonstrate that the proposed YOLOv8-RM algorithm outperforms other methods, achieving a detection accuracy of 91.8%, while also meeting the speed requirements for deployment on edge devices.

Oil and gas field surface systems are facing serious corrosion problems of metallic pipelines caused by CO 2 and H 2S. Although the traditional chip method of corrosion monitoring is feasible, it has limitations in terms of accuracy and real -time performance. In this study, the corrosion of 20# steel in a CO 2-H2S environment was systematically evaluated by simulating oilfield wastewater and experimental groups under different c onditions (single CO 2, H 2S, and a mixture of the two) using an innovative electrical resistance probe technique for monitoring corrosion in oilfields. The data analysis reveals the influence mechanism of corrosive medium on the monitoring accuracy of the r esistance probe, which provides scientific basis and technical support for improving the performance of the equipment and ensuring the safety monitoring of oil and gas pipelines containing hydrogen sulfide and carbon dioxide.

Pulsed Eddy Current Accurate Testing (INCOS) is a kind of non -destructive testing technology which can realize high precision and no omission in measuring pipe fitting, and has been widely used in petrochemical field. This content introduces the development history and domestic application of INCOS technology, focuses on the application and research progress in conventional equipment, pipelines, small nozzle, furnace tube (CFB, pulverized coal furnace, etc.), heat exchanger tube bundle, valve, tower wall, etc. And points out the existing problems and future development direction of INCOS technology. The INCOS (INsulated Component Scan test) technology is a comprehensive corrosion detection technology that uses a pulsed eddy current high - precision sensor (no more than 2cm in diameter) to fully scan equipment and process pipes. Also can quickly and accurately obtain the defect distribution, hidden danger location and severit y in the measured area, and provide data support for the maintenance and repair of equipment and process pipelines. Compared with the traditional pulse eddy current testing (by loading and turning off the current in the probe, this can excite a rapidly dec aying induced magnetic field, and then analyze the received induced signal to obtain the detection method of the metal wall thickness distribution), however, pulsed eddy current accurate testing is a method of detecting abnormal defects by continuously cut ting the volume of deposited metal and continuously calculating the change of pulse signal characteristic map under the volume. In order to ensure the accuracy of the test results, the defective abnormal areas are reinspected by ultrasonic and other techni cal means. INCOS technology pursues the accuracy and omission of test results. It uses pulse eddy current technology to quickly locate defects due to its convenient operation and high detection efficiency on the production site, and then uses other means t o assist in obtaining accurate results to meet the daily safety production needs of enterprises. Corresponding authors: tjt@incocorr.com. (J.T. Tao)

Abstract. Potential Matrix Mapping (PMM) represents a novel corrosion monitori ng technique that exhibits high accuracy and sensitivity. It is currently employed extensively in the online monitoring of corrosion in energy equipment. Its primary principle is to assess the corrosion of the internal wall of a metal structure by measuring the voltage change on its surface(Corcoran et al., 2020 , Ho et al., 2019). However, in the pitting corrosion signal analysis and inversion, the accuracy of the pitting corrosion morphology parameter detection is not sufficiently high(Gan et al., 2016). This paper proposed a calculation and analysis of the relationship between different pitting topography parameters and detection signals, based on the finite element method. A mathematical model and inversion algorithm for mapping between pitting morpholog y parameters and electric field characteristic signals have been established through multiple regression analysis and a neural network optimized based on a genetic algorithm. The issue of accurately resolving pitting morphological parameters has been resolved. The results of the numerical simulation and laboratory validation showed that both methods are effective in improving the computational accuracy of pitting signals in the PMM inspection technique. The algorithm based on multiple linear regression is more straightforward to implement, whereas the neural network -based algorithm exhibits a significantly lower relative error, with a relative error of less than 3% in its resolution of the pitting parameters. The aforementioned research offers a theoretical and technical foundation for the industrial implementation of PMM technology. Keywords. corrosion monitoring; numerical simulation; PMM; data Inversion

In nuclear power plants there are a large number of pipelines with insulation. In service, as a result of the external environment into the water or condensation of water, the pipeline occurred corrosion under insulation(CUI), which will give the safe operation of nuclear power units pose a major security risk, especially the CUI of important pipeline greatly affects the safe and stable operation of the unit.This paper focuses on the corrosion mechanism and influencing factors of CUI, and systematically analyzes and summarizes the existing corrosion monitoring t echnology methods.It takes the insulated pipe of the chilled water system of the nuclear power plant as the research object, and obtains the corrosion behavior law of the pipeline and the aging law of the coating through the on -site corrosion hanging test and on-site coating evaluation, so as to provide input conditions for the development of corrosion monitoring equipments of CUI.The developed equipment can monitor the main factors that cause CUI, through the temperature and humidity, corrosion current, co ating impedance and other parameters of real -time monitoring for pipeline repair program and overhaul plan to provide a key reference basis.

In this work, the EIS technology was used to study the cavitation erosion - corrosion mechanism of AA7050. EIS technology including charge transfer resistance, effective capacitance, and film resistance were used to characterize the electrochemical process during the cavitation erosion process. The whole cavitation erosion process can be divided into three stages: oncubation stage, acceleration stage and steady-state stage. The kinetic model of corrosion under cavitation erosion was proposed and its changes with the intensity and duration of cavitation were also discussed. Besides, charge transfer resistan ce can also distinguish the cavitation erosion mechanism well under different intensity of cavitation erosion resistance.

Superhydrophobic surfaces have attracted lots attentions of researchers due to their excellent water repellency, and are widely used in the fields such as anti - corrosion, anti-icing, anti-fouling, and self -cleaning. Herein, the authors used sim ple electrodeposition method to construct a series of superhydrophobic coatings on the surface of low-carbon steel, such as nickel (Ni), zinc nickel alloy (Zn Ni), porous zinc nickel cobalt (Zn Ni Co), multi -layer Ni/Cr, and other superhydrophobic surfaces. The porous nickel coating was also constructed by one step using the hydrogen bubble template method. The authors utilized electrodeposition technology to achieve a controllable construction of superhydrophobic coatings from one to multiple elements, from single to multiple layers. The influence of current density on the microstructure and wettability of the coatings was systematically investigated, and the relationship between microstructure and wettability was clarified. The corrosion resistance and long-term protection performance of superhydrophobic coatings were studied, and the anti-corrosion mechanism of superhydrophobic coatings was ultimately revealed.

mechanical properties and relatively low density. However, they possess poor corrosion resistance, limiting their applications. Detecting and imaging corrosion onset in coated magnesium alloys is crucial for preventing large -scale corrosion. However, imaging corrosion location and degree of corrosion poses significant challenges. Herein, a novel fluorescent sensor for imaging corrosion onset in magnesium alloys is synthesized by coating ZnO (ultraviolet-shielding shell, ZO) on ZnGa 2O4:Cr3+ (near-infrared ( NIR) signal source, ZGOC). The NIR emission and afterglow of ZGOC disappear after coating with ZnO. Because the alkaline environment formed following the corrosion of magnesium alloys can dissolve the ZnO shell, the NIR afterglow signal arising from ZGOC@ZO can accurately determine the location and degree of the corrosion. This nondestructive imaging technology using NIR -based ZGOC@ZO sensor demonstrates similar accuracy to that obtained through scanning electron microscopy and electrochemical impedance spectroscopy for the early corrosion detection of coated magnesium alloy. Moreover, this technology can detect corrosion onset earlier th an the laser confocal testing technology as well as locate and image the degree of corrosion of magnesium alloy. This work demonstrates the detection of corrosion onset in magnesium alloys, which can be extended to other metals. *Corresponding author: Professor Qi Zhu, E-mail: zhuq@smm.neu.edu.cn

offshore wind power installed capacity. However, offshore wind power installations are predominantly located in coastal areas with high humidity and salt spray, where wind power facilities are exposed to the marine atmosph eric environment for extended periods. This exposure leads to contamination of lubricants, accelerating the aging and deterioration of the lubricant, thereby hastening the wear and corrosion of bearings and gear workpieces. The synergistic effect of wear-resistant materials in mechanical and chemical media significantly reduces their service life, and gearbox failures or damage due to unit downtime are not uncommon. Friction and wear-induced corrosion have become key issues affecting the safe operation of o ffshore wind power, necessitating a deeper understanding of lubricant failure mechanisms and the friction and corrosion mechanisms of bearing materials in oil -phase media. This knowledge aids in the formulation of reasonable preventive measures and the regular replacement of lubricants. Zeng et al. investigated the corrosion behavior of M50 steel in brine-contaminated lubricating oil by immersing the steel in such lubricants and comprehensively characterizing localized corrosion areas on its surface. Howeve r, their study was conducted under static conditions, neglecting the synergistic effects of friction and corrosion in actual operating conditions, and it lacked an in -situ characterization method to understand the tribo -corrosion mechanisms of rolling bear ings. Electrochemical methods, with their fast response speed, low cost, and ability to obtain data quantitatively at regular intervals, are advantageous. However, due to the lower conductivity in oil-phase systems compared to aqueous media, electrochemical signals are weaker, and specialized device and method designs are often required. Yu et al. developed a ball -disc mini -traction tester and utilized a ball -disc two -electrode electrochemical testing system to analyze the oil film at different rotational s peeds, establishing the capacitive and impedance behavior and the relationship between impedance and oil film thickness. Nonetheless, the non -ideal two-electrode system used in their method is limited to electrochemical testing of pure oil phases and poses a risk of short-circuiting in brine-contaminated system. In this work, we designed a tribo -electrochemical device, as shown in Figure (a), for the study of tribo -corrosion process of steel in brine -contaminated lubricants. The electrochemical impedance sp ectroscopy results, as depicted in Figure (b), indicate that during the tribo-corrosion process, a water-in-oil emulsion is formed, reducing the corrosivity and increasing the capacitive loop over time. Conversely, when the tribo - corrosion process ceases, brine water deposition leads to increased corrosivity and a decrease in the capacitive radius over time in Figure (c). Figure: (a) Schematic diagram of the tribo-electrochemical test device, Nyquist diagram of PAO oil with 0.5% (v/v) NaCl solution added (15 N-100 rpm) under (b)dynamic and (c) static conditions (a) 0.0 2.0×105 4.0×105 6.0×105 8.0×105 1.20×105 2.40×105 3.60×105 4.80×105 6.00×105 –Z'' (W cm2) Z' (W cm2) 2 h 4 h 8 h 12 h Fitted line (b) 0.0 4.0×104 8.0×104 1.2×105 1.6×105 4.0×104 8.0×104 1.2×105 –Z'' (W cm2) Z' (W cm2) 2 h 4 h 8 h 12 h Fitted line (c)

Reinforced concrete, as a widely used material in construction engineering, directly impacts the service life and safety of structures. Over time, reinforced concrete structures are susceptible to corrosion and degradation due to various environmental factors, leading to reduced structural performance and even serious safety accidents. Traditional inspection methods typically rely on destructive testing, which, while assessing internal corrosion of reinforced concrete, often damages the structure and hinders continued use. In contrast, non -destructive testing methods primarily utilize techniques such as acoustics, optics, and electromagnetic ultrasonics. However, these methods often struggle to detect corrosion risks in the early stages, usually identifying severe corrosive damage only after it has occurred, thereby compromising the timeliness and effectiveness of protective measures. Therefore, it is necessary to explore non -destructive testin g methods. In this study, a novel reinforced concrete corrosion monitoring system was developed. This system monitors the internal corrosion of steel bars in reinforced concrete using indirect polarization technology. Simultaneously designed corresponding corrosion monitoring instruments, data centers, and sensors. Utilizing a four -electrode array sensor in conjunction with the corrosion monitoring device for signal excitation and data collection, the data center aggregates data from multiple corrosion moni toring devices and uploads it to cloud servers for computational analysis. This approach achieves real -time corrosion monitoring of in-service reinforced concrete structures, enabling timely identification of corrosion risks. Additionally, the study valida tes the accuracy and reliability of data obtained by the non-destructive monitoring devices through finite element simulation, ultimately ensuring comprehensive monitoring of the health status of concrete structures. The measured results are helpful to enh ance maintenance and reinforcement efforts, so as to safeguard the safety and reliability of engineering projects.

Boiler tube failures due to corrosion can lead to significant energy and economic losses, highlighting the importance of clean and efficient solid waste combustion. Investigating the corrosion mechanisms of key components during high -chlorine solid waste incineration and conducting in -situ online corrosion rate measurements are crucial for ens uring the safe and stable operation of boilers. This study employed electrochemical online monitoring, known for its sensitivity and importance in early detection. It was used to explore the corrosion mechanisms of TP347h heat exchanger tubes under various temperature gradients on the high -temperature flue gas side. Firstly, laboratory experiments were conducted with metal surface temperatures set at 450° C, 550° C, 650° C, and 800° C, while maintaining the flue gas temperature at 800° C to simulate the temperature gradient inside the furnace, and using incineration fly ash as the corrosive medium. Corrosion rates between 450° C and 650° C peaked at around 48 hours and increased significantly from 550° C to 650° C, indicating the activation of corrosion reactions. At 800° C, corrosion rates decreased due to the formation of dense chromium oxide layers. SEM analysis showed elemental stratification (Fe, Cr, Ni), and XRF results suggested that Na and Cl stabilized at 800° C by forming high melting point compounds, thereby reducing corrosion.Thereafter, field tests were conducted in a full-scale circulating fluidized bed (CFB) boiler in China, lasting for approximately 20 days. The steam temperature was around 450° C and the sampling port temperature was around 800° C. Results showed that corrosion rates surged initially as corrosive agents rapidly accumulated and penetrated the metal surface, but gradually decreased and stabilized as surface temperature dropped with continued deposition. This study Introduced an online system for monitoring ash deposition and corrosion rates, offering valuable guidance for optimizing material selection and anti -corrosion strategies in waste incineration processes.

The corrosion behavior of Q345 steel and Q235 steel in simulated soil solution was studied by corrosion immersion experiment. The corrosion experiment period was 1 year, and the factor affecting the corrosion was soil solution pH. Corrosion morphology (wh ether pitting occurs or not) at different pH was observed through corrosion immersion experiment, the corrosion rate was calculated, and the influence of pH value on pitting and crevice corrosion of Q345 steel and Q235 steel in soil environment was comprehensively analyzed. The experiment found that in pH10, 11 and 12 solutions, Q235 steel and Q345 steel showed pitting corrosion, and as pH increased, The average pitting depth increases. In the pH7 -13 range, Q235 steel is more sensitive to crack corrosion th an Q345 steel. Q345 steel experienced crack corrosion in solution of pH12, but no crack corrosion occurred in the other 5 pH conditions. Q235 steel has gap corrosion in the pH8.5-12 range, while no gap corrosion occurs at pH7 and pH13.

Nanocrystalline grains were fabricated on the surface layer of 7150 Al alloy by using ultrasonic shot peening treatment. The n anoscale corrosion behavior of this surface nanocrystallized 7150 Al alloy in 3.5 wt% NaCl solution was studied by combining focused ion beam (FIB) and transmission electron microscopy (TEM) techniques. It was found that, compared with the untreated substr ate alloy, pit corrosion is largely inhibited and intergranular corrosion (IGC) is eliminated on the surface nanocrystallized layer. The transition from IGC to uniform corrosion caused by ultrasonic shot peening can be attributed to the disappearance of precipitate free zone (PFZ) along grain boundaries. * Corresponding author; E-mail: sunqq7@mail.sysu.edu.cn * Corresponding author; E-mail: caofh5@mail.sysu.edu.cn

Potential Matrix Mapping (PMM, also known as Field Signature Method) method is a highly accurate and sensitive non -intrusive corrosion monitoring method, which has been successfully applied in submarine pip elines, oil refineries, bridge monitoring and other fields. However, due to the limitation of the weld -type electrode matrix, a set of PMM equipment can only monitor a fixed part. By separating the PMM corrosion detection equipment from the fixed position, the application field of PMM can be expanded, and the PMM can be developed from the corrosion monitoring method to the corrosion detection method. In this paper, two kinds of mobile electrode matrix schemes of assembled type and glue -packed type are desig ned and made for the typical application scenarios of flat plate and pipeline. Each electrode matrix scheme includes magnetic electrode structure, electrode limit structure and electrode matrix positioning structure. The assembled mobile electrode matrix a nd the glue -packed mobile electrode matrix were laid on the flat plate and pipeline for voltage signal reproducibility test to simulate the process of PMM corrosion detection. The test results show that the signal reproducibility of the glue-packed mobile electrode matrix is better than that of the assembled mobile electrode matrix. The reproducibility relative error of all channels is less than 5%, and the reproducibility relative error of most channels is less than 2%, which can meet the signal acquisitio n requirements of PMM corrosion detection. Finally, the mobile electrode layout and testing scheme of PMM corrosion detection are established, which have a certain guiding role for the standardization and standardization of mobile electrode layout of PMM detection methods.

This paper introduces the development and testing of an online local corrosion rate monitor based on Coupled Multi -Electrode Array System (CMAS) technology. During the design and development process, requirements such as data acquisition, communicat ion frequency, power supply, and storage were thoroughly considered. Additionally, the design and verification of the Zero Voltage Amperometry (ZVA) system were completed to ensure its accuracy meets the range of corrosion current measurement. Furthermore, the structural design of the probe was optimized to guarantee the accuracy of electrode arrangement, the reliability of electrical connections, and the sealing of the probe. Tests conducted in 3.5%wt NaCl solution demonstrate that the developed CMAS monit or can accurately reflect the changing trends of corrosion rates, achieving online monitoring of local corrosion.

Corrosion is a common matter,but the corrosion of overhead structures such as transmission towers, offshore wind power, and huge storage tanks in chemical plants is not readily observable. For the corrosion of these overhead structures, the traditional manual climbing observation is dangerous, and there is no indicator to determine the level of corrosion is very dependent on the experience of workers. Herein, we present a non -contact device and method suitable for corrosion level measurement of overhead structures. The non -contact device includes, among other parts, a drone, a non -contact photo-thermal sensor and a ground station. The non-contact device is carried by a drone to the vicinity of overhead structures, and the operator controls the ground station to obtain the thickness of the corrosion and rust layer in real time at the measured area from a distance. The thickness data of the corroded rust layer is measured by a non-contact photothermal sensor and returned to the operator as a numerical value. Field test flight results show that the device's maximum flight altitude of 50m, endurance time of 30 minutes, the farthest distance between the optical and thermal probe is 2m from the part being tested, without affecting the detection accuracy of the premise of the detection of the s tate of the maximum wind level 4, corrosion detection accuracy can be accurate to two decimal places. The device and method can solve the problem that the corrosion level of high-altitude structures is not easy to observe and can provide a basis for judgin g their corrosion level.

The corrosion of reinforced concrete structures in marine environment is serious, and the corrosion monitoring and detection of reinforced concrete is an effective means to control the risk of corrosion damage.In this paper, the common research methods of corrosion monitoring and detection of reinforced concrete are summarized respectively. Bec ause these methods have different working principles, different measurements and different advantages and limitations, it is necessary to know how to use each technology to maximize the value of corrosion monitoring and detection.Therefore, it can effectively support the reasonable decision-making process of the maintenance and repair of existing reinforced concrete structures. At present, the testing technology for reinforced concrete can be mainly divided into analytical methods, physical methods, electr ochemical methods, etc. The analysis method first involves on -site testing of parameters such as steel bar diameter, protective layer thickness, concrete strength, infiltration depth and content of harmful ions, longitudinal crack width, etc., and then analyzing the degree of steel bar corrosion in combination with the corrosive environment. The physical methods mainly characterize the corrosion of steel bars by measuring the changes in physical properties such as resistance, electromagnetic, thermal conductivity, and sound wave propagation caused by steel bars, including resistance bar method, eddy current detection method, X -ray method, infrared thermal imaging method, and acoustic emission detection method. Due to the fact that concrete corrosion in marine environments is an electrochemical process, electrochemical methods can better reflect the essence of its corrosion process. In addition, electrochemical methods also have advantages such as fast testing speed, high sensitivity, continuous tracking, and in-situ measurement, making electrochemical detection methods significantly advantageous in concrete corrosion detection. Common electrochemical methods include half cell potential method, electrochemical noise, cyclic voltammetry, polarization resistance, constant current polarization, pulse current, electrochemical impedance spectroscopy, etc. Among them, the AC impedance method has outstanding advantages such as high accuracy, not being affected by structural geometric factors, and being able to compreh ensively reflect the electrochemical process of corrosion, making it an ideal means of corrosion detection for reinforced concrete. However, there are still some urgent problems to be solved in the application of electrochemical impedance spectroscopy (EIS ) methods for testing on engineering sites, including the engineering application of complex EIS measurement equipment, extraction of surface corrosion signals of high impedance steel bars, and analysis of corrosion kinetics parameters of steel bars in com plex concrete corrosion systems. Finally, this article focuses on the application prospects and research priorities of electrochemical impedance spectroscopy in corrosion detection of reinforced concrete.

The measurement of corrosion of reactor materials is of guiding significance for the safe operation of reactors and can solve the engineering problem of material failure identification in nuclear power plants. 316H stainless steel has excellent corrosion resistance and i s widely used in the core structure and cooling system of nuclear power plants. The LIBS system for high temperature samples was built to measure 316H stainless steel on line. The system can control the ambient temperature of the sample and simulate the re actor condition. The variation of Fe, Cr, C, O and other elements with depth was deduced by combining the pulse times and the depth of the pulse pit, which provided a reference for judging the corrosion degree and corrosion mechanism. The experimental resu lts accumulate experience and data for the evaluation of corrosion properties of structural materials used in reactors under high temperature environment using LIBS.

This paper introduces the development and testing of an online local corrosion rate monitor based on Coupled Multi -Electrode Array System (CMAS) technology. During the design and development process, requirements such as data acquisition, c ommunication frequency, power supply, and storage were thoroughly considered. Additionally, the design and verification of the Zero Voltage Amperometry (ZVA) system were completed to ensure its accuracy meets the range of corrosion current measurement. Furthermore, the structural design of the probe was optimized to guarantee the accuracy of electrode arrangement, the reliability of electrical connections, and the sealing of the probe. Tests conducted in 3.5%wt NaCl solution demonstrate that the developed C MAS monitor can accurately reflect the changing trends of corrosion rates, achieving online monitoring of local corrosion.

Anti-rust oils (ARO) is a high efficiency -cost anti -corrosion technique to inhibit the atmospheric corrosion of metal parts and equipment. However, in contaminant or coastal environments, salt particles, aerosol, CO2, SO2, etc., may intrude into the oil layer, leading to the early failure of AROs. In this work, we first prepared a kind of ARO made of sodium petroleum sulfonate (SPS) inhibitor and white oil, then coated the ARO on a mild steel plate to investigate the deterioration process of AROs beneath saline water droplets by Quartz crystal microbalance (QCM) and electrochemical map ping techniques. It shows that the SPS concentration is crucial to the ARO inhibition property. When the SPS content is lower than its critical micelle concentration (CMC), saline droplets may permeate the barrier formed by the nonpolar paraffin groups of SPS and then adsorb on the steel surface, resulting in localised corrosion. However, once the SPS content exceeds its CMC, the saline droplets will be emulsified and captured in the oil phase by the reverse micelle effect, thus inhibiting the corrosion of steel substrates. The microstructure of the oil -water interface was characterised by micro-infrared spectroscopy techniques, showing that the surfactant molecules can transform water molecules from free to bo nded water molecules through oriented adsorption, thus offering protection against the intrusion of saline droplets. In contrast, concentrated NaCl saline(>0.5 droplets may disrupt the bo nded state of water molecules, decreasing the arresting ability of AROs on saline droplets. Moreover, wire beam electrodes (WBE) and thin electrical resistance (ER) techniques were employed to probe the atmospheric corrosion of mild steel under AROs, and it evidenced that the ER is better at evaluating the inhibition perf ormance of AROs than traditional electrochemical methods.

Poly(dimethylsiloxane) (PDMS) coatings are considered to be environmentally friendly antifouling coatings. However, the presence of hydrophobic surfaces can enhance the adhesion rate of proteins, bact eria and microalgae, posing a challenge for biofouling removal. In this study, hydrophilic polymer chains were synthesised from methyl methacrylate (MMA), Poly(ethylene glycol) methyl ether methacrylate (PEG -MA) and 3 -(trimethoxysilyl) propyl methacrylate (TPMA). The crosslink-ing reaction between TPMA and PDMS results in the formation of a silicone-based amphiphilic co-network with surface reconstruction properties. The hydrophilic and hydrophobic domains are covalently bonded by condensation reactions, while the hydrophilic polymers migrate under water to induce surface reconstruction and form hydrogen bonds with water molecules to form a dense hydrated layer. This design effectively mitigates the adhesion of proteins, bacteria, algae and other marine organisms to the coating. The antifouling performance of the coatings was evaluated by assessing their adhesion rates to proteins (BSA -FITC), bacteria (B. subtilis and P. ruthenica) and algae (P. tricornutum). The results show that the amphiphilic co-network coating (e.g., P -AM-15) exhibits excellent antifouling properties against protein, bacterial and microalgal fouling. Furthermore, an overall assessment of its antifouling performance and stability was conducted in the East China Sea from 16 May to 12 September 2023, which showed that this silicon-based amphiphilic co-network coating remained intact with almost no marine organisms adhering to it. This study provides a novel approach for the development of high -performance silicone -based antifouling coatings.

Titanium has great potential for application in the marine engineering due to its corrosion resistance, low density, and chemical stability, but titanium is also prone to suffer from marine biofouling, thus limiting its further development. Completely filling the interior of TiO 2 nanotube arrays, generated by electrochemical anodizing on the titanium surface, with Cu 2O, a biocide widely used in anti -fouling coatings, seems to be a promising approach for developing a novel biocidal anti -fouling titanium surface. The tubular structure of TiO 2 nanotube arrays not only loads a large amount of Cu 2O but also slows down its release rate in the marine environment. Herein, we devised an innovative and simple two -step electrochemical approach to completely fill TiO2 nanotube arrays with Cu2O. This approach involves a precise cathodic polarization to selectively enhance the bottom conductivity of TiO 2 nanotube arrays, followed by an optimized pulsed deposition to fill Cu 2O. EIS and Mott -Schottky plots results showed that after cathodic polarization of TiO 2 nanotube arrays at −1.7 V (vs.SCE) for 60 s in 1 mol/L (NH 4)2SO4 aqueous solution, the charge transfer resistance Rbl of the inner barrier layer decreased by two orders of magnitude, while the charge transfer resistance Rnt of the outer nanotube layer remained unchanged, and the carrier density increased by four orders of magnitude. The selective enhancement of the bottom conductivity of TiO2 nanotube arrays resulted in the nucleation of Cu 2O at the bottom and growth along the bottom-to-top direction during pulse deposition. Laboratory anti-adhesion experiments demonstrated that the completely filling of Cu 2O into TiO 2 nanotube arrays showed remarkable effectiveness against marine bacteria ((99.51 ± 0.17) % for Bacillus sp.), marine diatoms ((99.60 ± 0.13) % for P. tricornutum), and barnacles ((100 ± 0) %). Furthermore, the completely filling of Cu2O into TiO2 nanotube arrays also exhibited a durable resistance to P. tricornutum adhesion for up to 49 days ((99.52 ± 0.15) %) in the laboratory and prevented barnacle settlement for 20 days in the marine environment. This preparation method of the complete filling of Cu 2O into TiO2 nanotube arrays offers a promising and reliable strategy to address the marine biofouling problem of titanium.

Considering the extensive application of titanium alloys in naval seawater pipelines and their suscept ibility to marine biofouling, this study has successfully developed carbon nanodots (CDs) derived from levofloxacin as a precursor. These carbon dots, as a new type of metal -free artificial nanoenzyme, were modified with a silane coupling agent and combine d with organic monomers using ultraviolet (UV) curing technology to form a film in situ on the surface of titanium alloys. The film not only retains the bactericidal properties of levofloxacin but also exhibits catalytic activity similar to that of oxidase s, effectively inhibiting the formation of marine bacterial biofilms and the adhesion of diatoms. After a two -month real -sea hanging panel experiment, the film showed superior antifouling effects compared to the unmodified titanium alloy surface, providing an effective protective strategy for the long -term application of titanium alloys in marine environments, with significant scientific and application value.

Ultrasonic technology has drawn a resurgence of interests for its great potential in marine antifouling applications. However, its effects on the adhesion behavior of marine fouling organisms on marine structures remain underexplored. This work has investigated how ultrasonic treatment impacted the adhesion of Pseudoalteromonas on the marine epoxy primer. And the process parameters for ultrasonic treatment were optimized using response surface analysis of Design-Expert software. The results revealed that ultrasonic treatment disrupted the cellular structure of Pseudoalteromonas, causing deformation and fragmentation of cell membrane, leading to the bacterial death. Additionally, ultra sonic treatment reduced the particle size and zeta potential value of Pseudoalteromonas, which disrupted the stability of bacterial suspensions. It also increased the relative surface hydrophobicity of Pseudoalteromonas cells, resulted in the reduction of the adhesion to the marine epoxy primer. This study demonstrated that ultrasonic treatment has significantly disturbed the adhesion behavior of microorganisms like Pseudoalteromonas on the marine epoxy primer, which provided an effective approach for controlling marine biofouling.

Bioinspired slippery surfaces have garnered significant attention as promising solutions to mitigate biofouling. Unlike traditional lubricant -infused porous surfaces, recent research has focuse d on the integration of lubricants within polymer brush-grafted surfaces. The combination of polydimethylsiloxane (PDMS) polymer brush and silicone oil has gradually become the most prevalent choice due to their outstanding chemical affinity. However, this conventional coating system also has the potential for improvement to meet the needs of long -lasting and efficient marine antifouling, including i) precisely designing the polymer brush’s chemical structure to match the polarity of a specific lubricant en hances their chemical affinity, and ii) appropriately reduce the coating system’s surface energy to improve the fouling desorption performance. Here, we introduce a systematically engineered polymer brush/lubricant coating system that incorporates fluorina ted polysiloxane and perfluoropolyether fluid. This novel coating system exhibits enhanced adhesion strength coupled with reduced surface energy, resulting in superior stability and omniphobic properties. Additionally, it showcases excellent corrosion resi stance and significantly deters marine microorganism adhesion, achieving reductions of 98.8% for P. tricornutum and 99.8% for Bacillus sp.. Marine field trials, conducted over a 90-day static immersion period, confirm the remarkable antifouling performance, which surpasses most existing slippery coatings. Moreover, under dynamic conditions, organisms adhering for 150 days are readily dislodged by shear force. These findings underscore the pivotal role of systematic design in polymer brush/lubricant coating systems for the advancement of high-performance slippery surfaces tailored for marine antifouling applications.

The ballast tank of a ship is a compartment used to maintain the balance and stability of the vessel, ensuring it maintains a certain draft depth. It requires frequent ballasting and discharging of seawater, which is typically rich in microorganisms. The repeated inflow and outflow of water lead to sediment buildup at the bottom of the tank, creating a relatively stable environment that promotes microbial growth, thereby accelerating the corrosion of materials in the ballast tank due to microbial influence. By incorporating bactericidal quaternary ammonium salts (QAS) into the epoxy anticorrosion coating and adjusting their proportion in the resin, the coating achieves its bactericidal effect through the interaction between QAS and the cell membranes. By chemically bonding the quaternary ammonium salt to the polymer matrix in the coating, the loss of antimicrobial active ingredients can be effectively avoided. The antimicrobial coating tests conducted in the laboratory showed that the coating exhibited an inhibition rate of over 99% against typical Gram-positive bacteria Staphylococcus aureus and Gram -negative bacteria Escherichia coli. It also demonstrated an inhibition rate of over 99% against the typical anaerobic corrosion bacterium Sulfate-Reducing Bact eria (SRB). The introduction of QAS into the anticorrosion coating effectively resists microbial growth, thereby reducing the occurrence of microbial corrosion and mitigating corrosion issues in ballast tanks caused by microorganisms.

The blockage of seawater pipelines caused by the attachment of marine organisms seriously affects the safety and life of service equipment. Chlorine production by electrolysis of seawater has attracted extensive attention as a simple and efficient method to prevent biofouling. Polymetallic oxide electrode (DSA) is a commonly used chlorine anode, which is generally coated on the surface of a titanium substrate, and the main component is an oxide formed by ruthenium (Ru), iridium (Ir), titanium (Ti) and other metals. At present, the high cost, Ru degradation, coating peeling, substrate passivation and other problems of DSA electrode have seriously affected its wide application in the field of anti-biofouling, among which coating peeling is the key to affecting the life of the electrode. In order to explore the effect of the surface structure of the titanium substrate on the adhesion between the coating and the substrate, the effect of the surface structure of the titanium substrate on the solid solution adhesion of Ru Ir Co Ni was investigated by hydrochloric acid etch ing. In this study, hydrochloric acid with different mass fractions (5%, 10%, 15%, 20%, 25%) was used to etch Ti matrix at room temperature and pressure. The electric double -layer capacitance of the titanium sheet with hydrochloric acid etching with 20% mass fraction was the largest, and the charge transfer resistance Rct was the smallest, which was 0.2165Ω·cm2, which meant that the titanium substrate treated under these conditions had the least influence on the chlorine evolution reaction. Fig. 1(A) Schematic diagram of the application of electrolytic seawater antifouling technology in seawater pipelines; (B) Relationship between Rct and C with HCL concentration;

Purpose: Optimizing the impressed current from auxiliary anode during lifetime protection period based on simulation, preventing potential of jacket from over-protection and under-protection. Method: By means of establishing cathodic protection model, adjusting coating damage rate and exchange current density, calculating impressed current, the impressed currents are optimized based on simulation. Research: At the early stage of protection, the potential remains almost unchanged, because of the small coating damage rate. At the later stage of protection, the potential gradually moves in the positive direction; The further the auxiliary anode s are from jacket, the more uniform the potentials are, and vice versa, the more uneven they are; The area where the jacket is closest to the auxiliary anode has the highest c urrent density and is prone to over -protection. Conclusion: There is insufficient protection when calculating the impressed current cathodic protection of the jacket based on the traditional specification; The finite element method can be used to optimize the calculation quickly and determine the minimum impressed current required; When calculating impressed current based on traditional specification, the value of impressed current from auxiliary anode should be increased in the later stage, avoiding under - protection; The impressed current in the early stage can be appropriately reduced which meet the necessary protection requirements; The closer the area is to the auxiliary anode, the more uneven the potential distribution of the jacket, and vice versa, the more uniform it is.

As a sustainable and efficient approach to marine resource development, marine pastures are gaining increasing recognition in the global aquaculture industry. However, various facilities within these environments, such as cages, buoys, ropes, and pipes, are highly susceptible to biofouling. Biofouling increases the weight and hydrodynamic resistance of structures, causing material wear, corrosion, and reduced service life. It also negatively impacts environmental factors like water flow and light penetration. These changes can deteriorate the quality of the aquaculture environment and elevate the risk of infectious diseases among cultured species. Consequently, the effective prevention of biofouling is critical to ensuring the sustainability and economic viability of marine pastures. To address this challenge, a polydimethylsiloxane (PDMS)-modified phenolic resin has been utilized as a coating material to enhance surface hydrophobicity and provide improved elasticity and flexibility. In addition, halloysite nanotubes were surface -modified by introducing smart -responsive organic chains and grafting natural organic biocides, while concurrently loading metal nanoparticles. This innovative anti -corrosion and antifouling nanocomposite coating significantly enhances the coating's density and resistance to biofouling. Antimicrobial tests demonstrated that this na nocomposite exhibits long -lasting bactericidal effects against Bacillus and Pseudoalteromonas species. This multifunctional coating material presents a promising solution for protecting marine ranch facilities from corrosion and biofouling, thereby supporting their sustainable development and improving economic outcomes.

In order to improve the corrosion resistance of B30 copper nickel al loy and explore the optimal conditions for the composite use of benzotriazole (BTA) and methylbenzotriazole (TTA), an orthogonal experimental design was adopted to analyze the effects of BTA concentration, TTA concentration, film formation time, and film formation temperature on the corrosion resistance of B30 copper nickel alloy through electrochemical impedance spectroscopy, SEM images, energy spectrum analysis, polarization curve testing, and weighing method. The optimal experimental conditions obtained through the above experiment are 5 g/L of BTA, 2.5 g/L of TTA, film formation temperature of 40 °C, and film formation time of 3 hours. The influence of various factors, from primary to secondary, is as follows: film-forming temperature> BTA>film-forming time> TTA. After the composite use of BTA and TTA, it can be seen in the SEM image that the pore radius and porosity decrease, and the average corrosion current density decreases by 30%. Under certain conditions, the combined effect of two corrosion inhibitors is improved compared to using them alone.

Degradable self-polishing antifouling coatings are expected to be the next generation of antifouling coatings due to their excellent environmental friendliness and static antifouling effect. However, the polishing process and mechanism are still unclear. In this work, steered molecular dynamics (SMD) simulations were conducted to investigate the detaching process and mechanism of the degraded main chain (DMC) and the antifouling agent, and the influence of substrate hydrolysis degree was also studied. The results show that without water scouring, the DMC and antifouling agent molecules are always adsorbed to the coating surface in a static environment due to the non -bonding interaction of the substrate. The strong interaction between the substrate and the wat er molecules can form a water film that hinders the detaching process. The non-bonding interactions from the substrate, the encroachment of water molecules on the hydrogen bonding sites of the clusters, and the unevenness of the substrate surface always pr event the clusters from being detached completely. This work elucidates the microscopic process and mechanism of main chain degradable self-polishing antifouling coatings in the presence of seawater and also sheds light on the direction of optimizing degra dable self -polishing coatings for accelerating their commercialization application.

A series of acrylic -based self -polishing composite coatings with excellent antifouling properties (BAP/GNG) are prepared, including the modulation of the content of monomers and the introduction of graphene -analogous 2D materials. Pyridinetriphenylborane is grafted in acrylic resin, which can be hydrolyzed in seawater to form a continuously renewed dynamic surface. The addition of graphene-analogous 2D materials to acrylic resins not only regulates the hydrolysis rate to enhance the antifouling ability of acrylic composite coatings but also provides photocatalytic properties to acrylic composite coatings. BAP/GNG composite coatings exhibited excellent algae anti -adhesion performance. Specifically, the inhibition rate of Phaeodactylum tricornutum reached 99.2%, and high antibacterial rates of up to 94.2% and 95% were obtained for Escherichia coli and Staphylococcus aureus, respectively. At the same time, the dynamic surface produced by hydrolysis are effectively able to inhibit mussel adhesion. Such functional acrylic -based self -polishing composite coatings show promise as an antifouling coating with potential applications in marine antifouling.

Macrophages can kill bacteria and viruses by releasing free radicals, which provides a possible approach to construct antifouling coatings with dynamic surfaces that release free radicals if the breaking of dynamic covalent bonds is precisely regulated. Herein, inspired by the defensive behavior of macrophages, a marine antifouling coating composed of polyurethane incorporating dimethylglyoxime (PUx - DMG) is prepared by precise regulation of dynamic oxime -urethane covalent bonds. The obtained alkyl radical (R· ) derived from the cleavage of the oxime-urethane bonds manages to effectively suppress the attachment of marine biofouling. Moreover, the intrinsic dynamic surface makes it difficult for biofouling to adhere and ultimately achieves sustainable antifouling property. Notably, the PU 50-DMG coating not only presents efficie nt antibacterial and antialgae properties, but also prevents macroorganisms from settling in the sea for up to 4 months. This provides a pioneer broad-spectrum strategy to explore the marine antifouling coatings.

The Ru0.3LaxTi(0.7-x) electrodes are made by sol -gel method. The effect on chlorine evolution performance, st rengthening life and surface morphology of electrodes doped with La 2O3 are studied. Results: The titanium etched by acid and then alkali has a large specific surface area, while the titanium etched by acid had no obvious nanopore; The incorporation of La 2O3 could reduce the film resistance and electrochemical transfer resistance of the electrode, enhance the conductivity of the coating; The electrode doped with 1% La 2O3 coating has a smaller electrochemical transfer resistance than Commercial DSA under the same unit molar mass of Ru, which will reduce the cost of Ru; The electrode doped with 1% La2O3 has the highest reaction rate constant among the electrode doped with 0%La 2O3, 2%La2O3 and 3% La2O3; The electrode doped with 1% La 2O3 has higher life than the electrode doped with 2% La2O3 and 3% La2O3.

Macrofouling adhesion can increase the hydrogen permeation and SCC sensitivity of high -strength steels, but related research needs to be refined. A field exposure test was set up to study the ef fect of macrofouling adhesion on hydrogen permeation and stress corrosion cracking (SCC) behaviors of a high -strength steel in marine immersion zone, and the results were further verified by laboratory electrochemical simulation tests. The results indicated that the crevices formed by macrofouling adhesion ( Fig. 1) can promote localized corrosion pits and change the local chemical environment on the surface of high-strength steel under natural corrosion and cathodic protection state. More severe localized corrosion can increase the hydrogen permeation current density and promote the SCC of high -strength steel under natural corrosion state. As a comparison, the hydrogen permeation current density of steel under cathodic protection state was slightly decrease d owing to the shielding effect of macrofouling. Meanwhile, the macrofouling increases the SCC sensitivity of high-strength steel under cathodic protection state by promoting localized corrosion.

H. illucens larvae were immunologically induced by D. vulgaris. The functional classification of GO (Gene ontology) and the enrichment of KEGG (Kyoto encyclopedia of genes and genomes) signal pathways were analyzed respective ly, respectively. An antimicrobial peptide prediction tool based on machine learning algorithm was used to predict the antimicrobial activity of peptides with different expression. Four novel antimicrobial peptides with the highest antibacterial fraction (DH-1, DH -2, DH -3, DH -4) were synthesized in solid phase and the highest antibacterial activity (AIGVKTLGAGLGYSSGWSHGLI) was selected through antibacterial performance test. The combination of DH -1 and THPS can reduce the dosage of fungicide by more than 60 %, and the strengthening effect of fungicide is more significant, which may be attributed to the fact that DH-1 contains a large number of hydrophobic amino acids, which increases the permeability of bacterial cell membrane and makes it easier for fungicid e to enter the cell interior. Using a new natural antimicrobial peptide DH-1 as a green antifouling agent and Mesoporous silica nanoparticle (MSN) as a nanostorage container, Using Tannic acid (TA) and Fe( III) complex (TA-Fe(III) complex (TAC) as nanovalves, a sulfur ion intelligent response antibacterial peptide -based antiseptic antifouling coating was successfully prepared (FIG. 1). The results showed that MSN-DH-1@TAC coating had no effect on the growth and metabolism of planktonic bacteria, but could inhibit the adhesion of d significant antibacterial activity when combined with 80 ppm THPS, saving more than 60% of the amount of fungicide compared to the high concentration fungicide alone. After soaking in the actual Marine environment for 3 months, the antifouling performance of MSN - DH-1@TAC coating is significantly improved compared with the blank coating, as shown in FIG. 2. FIG. 1. Design and preparation of intelligent response antimicrobial peptide coating FIG. 2. Surface morphology of blank coatings (a1-a3) and MSN-DH-1@TAC coatings (b1-b3) after soaking in a sea environment for 3 months and the abundance of bacterial communities attached to their surfaces at the door level

Corrosion poses a ubiquitous and costly challenge for diverse industries, primarily contributing to marine mechanical failures, metal degradation, service inefficiency and insecurity. To mitigate the almost 3.34% of gross domestic product losses attributed to corrosion in China, the lifespan of metall ic structures, as the cornerstone of their design, is of paramount importance, as it determines their complete functional failure from the moment they enter service. Herein, drawing upon our previous researches, we capitalized on the potential of a pH-responsive switch on the surface of HNTs as the composite filler to precisely control the release of corrosion inhibitor under acidic, neutral, and alkaline conditions. It effectively impedes the permeation of corrosive media within the composite epoxy coating system, thereby inhibiting the progression of corrosion on the metal surface. The results specifically showed that after 63 d of immersion, the |Z|0.01 Hz value of the composite epoxy coatings (containing 0.5 wt% composite filler) remained at 9.98 × 10 9 ohm·cm2 , which was two orders of magnitude higher than that of the pure EP coatings, due to the multifunctional role played by the nanoparticles in active corrosion inhibition, anodic passivation and physical shielding. In conclusion, this study provides a potential strategy for formulating coatings with durable anticorrosive properties, offering promising prospects for industrial applications in harsh environments.

In this work, a versatile strategy of defective metal organic frameworks (MOFs) manipulated with the assistance of the steric hindrance effect was proposed and applied in anticorrosion and antifouling coatings. The steric hindrance effect was utilized to construct the defective zeolite imidazole frameworks (ZIFs) by phosphate, gluconate and phytate as classic examples. The defective MOFs, Phosphate -ZIF-7, Gluconate-ZIF-7 and Phytate-ZIF-7, were successfully synthesized by de novo method. The preparation process of defective ZIFs was environmentally friendly in aqueous solution at room temperature. The anions with different steric hindrances have an impact on the morphology and s tructure of defective MOFs, which can be tailored to form spherical, lamellar, or irregular shapes. As the steric hindrance of anions gradually increases, the absolute value of zeta potential gradually increases, elaborating that the stability of defect-engineered ZIF-7. The as-tailored defects in nanoparticles make the molecular chains of polymers permeate into the internal skeleton to form the interlocking structure, improving the comprehensive properties of coatings at molecular level. The mechanical properties of waterborne acrylic resin were improved remarkably after embedded with defective ZIF-7. The defective MOFs were added in waterborne acrylic resin to improve the corrosion protection performance. The structure-property relations were elaborated by molecular dynamics simulation and relevant experiments in detail.

Marine antifouling coatings can effectively keep ship hulls free from the adhesion of marine organisms, thereby preventing increased ship sailing resistance, operating costs and carbon emissions [1]. However, due to the long evaluation period and the increasingly strict environmental regulations, developing long-term antifouling coatings has become a challenging task. In this paper, the research progress of the self -polishing coatings based on ion exchange, hydrolyzable or degradable polymers and the fouling release coatings based on silicone elastomers is reviewed[2,3]. Additionally, this paper also presents the research progress of laboratory and real -sea performance evaluation techniques. To further shorten the evaluation period and develop long-acting antifouling coatings, we established a rapid laboratory optimization method for antifouling coatings. By using orthogonal experiment design, the influences of pigment volume concentration (PVC), resin/rosin mass ratio and the amount of additives (R) on the biocides release rate and adhesion of coatings were studied, and the optimal value of PVC, resin/rosin mass ratio and the amount of additives (R) were obtained[4]. Based on the above methods, we have developed a series of novel degradable self - polishing coatings for different applications. Such coatings have been widely used because of their good antifouling performances and drag reducing properties.

Seawater culture cages have always been plagued by the problem of marine biofouling in the process of aquaculture. This problem may decrease the permeability of cages, block water flow exchange, affecting the quality of aquaculture organisms, and even lead to the death of aquaculture organisms, resulting in huge economic losses[1]. The marine antifouling coating is one of the most economical and effective ways to protect the cages from marine biofouling. However, the copper ions released by cuprous oxide antifouling coatings widely used in aquaculture will accumulate in organisms, causing serious harmful effect to ecological environment [2]. In this study, a series of allicin grafted acrylic self -polishing anti -fouling resin was synthesized by free radical polymerization. Bacteriostasis experiment and immersion experiment were carried out to inspect the antifouling property and self-polishing rate. The results showed that the antibacterial rate increase with the increased allicin content, and the sel f-polishing rate can reach 8.83 g ·d-1·m-2. The allicin antifouling coatings (AAC) made from allicin grafted acrylic self -polishing anti -fouling resin showed outstanding flexibility and adhesion force towards fish nets without particles, blisters and fragments during 10 month filed test in the Bohai Sea. The bright and clean fish nets verified the excellent antifouling performance of AAC. In order to investigate the feeding effect of AAC, the growth rates of zebrafish were tested. The results showed that the growth rate of zebrafish in the water tank soaked with AAC was 6.14% higher than that in the blank water tank, which proved that AAC not only cause no harm to zebrafish, but even had a feeding effect. It can greatly shorten the aquaculture cycle of aquatic products.

Marine biofouling has always pos ed a significant challenge for the marine industry. Fouling-release coatings (FRCs) are commonly used in marine anti -fouling due to their low cost and environmentally friendly properties, among which silicone - based coatings with low surface energy are most widely used. In this study, we successfully prepared a novel nano-enzymatic composite low-surface-energy coating by modifying silicone with polyurethane and incorporating nano -Cu which exhibits peroxidase-mimicking activity. Firstly, we modified the nano -Cu using isophorone diisocyanate (IPDI) and polyethylene glycol (PEG). Characterization via x -ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), x -ray photoelectron spectroscopy(XPS), and scanning electron microscopy(SEM) confirmed the successful modification. Then we synthesized the silicone-based polyurethane coating through a two -step process, utilizing IPDI, bis -hydroxy-capped polydimethylsiloxane (HO-PDMS-OH), and 4,4' -methylenebis(3-chloro-2,6-diethylaniline) as raw materials. Ultimately, we obtained the nanocomposite low-surface-energy coatings by adding 0.1 wt% of nano -Cu to the aforementioned coatings. We tested the water contact angle (WCA) of the coating surface and performed surface free energy (SFE) calculations. The results indicated that the contact angle shifted from 103.8° to 97.6° after adding modified nano-Cu, while the surface energy changed from 22.3 mJ/m2 to 21.6 mJ/m2 , demonstrating that the coating retains its hydrophobicity and low surface energy properties. Furtherm ore, we evaluated the antifouling performance of the coatings through antibacterial and anti -diatom experiments. The bactericidal rate of the composite coatings containing nano -Cu reached 97%. In the presence of trace amounts of H 2O2, the bactericidal rate approached nearly 100% due to the mimetic peroxidase activity of the nano -Cu. In conclusion, this study presents a promising pathway for developing high -performance silicon -based antifouling coatings, which hold great potential for real-world marine antifouling applications.

Surface coatings designed to mitigate pervasive biofouling herald a new era of surface protection in complex biological environments. However, existing strategies are plagued by persistent and recurrent biofilm attachment, desp ite the use of bactericidal agents. Herein, we develop a chiral metal -organic framework (MOF) - based coating with conformal microstructures to enable a new anti -biofouling mode that involves spontaneous biofilm disassembly followed by bacterial eradication. A facile and universal metal -polyphenol network (MPN) is designed to robustly anchor the MOF nanoarmor of biocidal Cu 2+ ions and anti -biofilm D-amino acid ligands to a variety of substrates across different material categories and surface topologies. Incorporating a diverse array of chiral amino acids endows the resultant coatings with widespread signals for biofilm dispersal, facilitating copper -catalyzed chemodynamic reactions and inherent mechano -bactericidal activities. This synergistic mechanism yields unprecedented anti -biofouling efficacy elucidated by RNA -sequencing transcriptomics analysis, enhancing broad-spectrum antibacterial activities, preventing biofilm formation, and destroying mature biofilms. Additionally, the chelation -directed amorphous/crystalline coatings can activate photoluminescent properties to inhibit the settlement of microalgae biofilms. This study provides a distinctive perspective on chirality-enhanced antimicrobial behaviors and pioneers a rational pathway toward developing next-generation anti-biofouling coatings for diverse applications.

Developing environmentally friendly, broad -spectrum, and long -lasting antibacterial materials remains chall enging. Our ternary BiOI@Bi 2S3/MXene composites, which exhibit both photothermal therapy (PTT) and photodynamic therapy (PDT) antibacterial properties, were synthesized through in-situ vulcanization of hollow flower-shaped BiOI on the surface of two-dimensional Ti3C2 MXene. The unique hollow flower-shaped BiOI structure with a high exposure of the (001) crystal plane amplifies light reflection and scattering, offering more active sites to improve light utilization. Under 808 nm irradiation, these composites achieved a photothermal conversion efficiency of 57.8%, boosting the PTT antibacterial effect. The heterojunction between Bi2S3 and BiOI creates a built -in electric field at the interface, promoting hole and electron transfer. Significantly, the close -contact heterogeneous interface enhances charge transfer and suppresses electron -hole recombination, thereby boosting PDT bacteriostatic performance. EPR experiments confirmed that ∙O2− and •OH radicals play major roles in photocatalytic bacteriostatic reacti ons. The combined antibacterial action of PTT and PDT led to efficiencies of 99.7% and 99.8% against P. aeruginosa and S. aureus, respectively, under 808 nm laser irradiation. This innovative strategy and thoughtful design open new avenues for heterojunction materials in PTT and PDT sterilization.

Marine biofouling is a maj or problem deteriorating the service performance and lifespan of marine infrastructures. Developing a durable, long -term and environmental-friendly antifouling coating is therefore of significant importance but still a critical challenge in maritime engine ering. Herein, we developed two types of long - term durable antifouling coatings by plasma spraying. The one is a composite Cu -X coating (X is a kind of metal with more positive potential than Cu) with novel micron - sized alternating Cu/X laminated -structure This coating was designed to controlled release Cu ions by galvanic dissolution of Cu laminates from the Cu/X micro -galvanic cell in aqueous solution, and therefore to achieve long -term, self -polishing and environmental-friendly antifouling capability wit h high mechanical durability simultaneously. The other is a micro/nano bimodal porous -structured slippery liquid infused porous surfaces (SLIPS) coating. The effect of spraying parameters on the coating microstructure and long-term antifouling performances were investigated and the underlying mechanisms were revealed. In the case of the Cu -X coating, results showed that remarkable antifouling efficiency against bacteria survival and adhesion up to ~100% was achieved. Cu/X micro - galvanic cell was confirmed to be formed within Cu-X coating and responsible for the Cu ions release and its excellent antifouling performance. For the SLIPS coating, it demonstrated superior reduction rates of 87 %, 92 %, and 94 % for the settlement of E. coli, Chlorella, and P. tricornutum, respectively, after 20 days of incubation assay. These two novel coatings would provide new and effective antifouling strategies in maritime engineering.

Nanomaterials play an important role in improving the mechanical properties of organic anti -fouling coatings. The influence of different types of nanomaterials on organic coatings was studied in this work. The nanomaterials studied mainly include TiO2, ZnO, g-C3N4. Among them,TiO 2 was spherical, ZnO was flower shaped, and g-C3N4 was layered. The main component of organic coating is water-based acrylic resin. The mechanical properties of the acrylic resin coating are all improved when the three types of nanomaterials mentioned above are added. The density of the coating has also been improved due to the addition of the.nanomaterials.

Marine equipment is frequently attacked by intricate fouling, resulting in a series of problems, such as reduced operational lifespan and biological encroachments. To date, the use of antifouling coatings is considered to be the most effective, cost-effective and widely applied strategy. Constructing anti-fouling coatings containing dynamic surfaces can effectively prevent the adhesion of marine foulin g organisms. Dynamic surfaces can shorten the contact time between organisms and surfaces so that their interactions are close to non-adhesive collisions, which reduces the interaction force with fouling organisms and facilitates their escape. Based on this strategy, we have successfully constructed a series of antifouling coatings with dynamic surfaces. In order to combine the antifouling advantages of dynamic surfaces and avoid the impact of antifouling agents on the metabolism and growth of nonspecific target organisms, natural antifouling functional groups were immobilized into the dynamic resin structure via covalent bonds. Therefore, synergistic inhibition of fouling adhesion by the natural antifouling functional groups and the dynamic surfaces is achieved. These findings emphasize the critical role of molecular structure design in coating systems to advance interfaces tailored for marine antifouling applications.

Improving the utilization rate of environmentally friendly antifouling agents is highly important for reducing the economic costs of ship operations and protecting the marine environment. In this work, a new method for preparing a multistage controlled release material of an environmentally friendly antifouling agent, wh ich first incorporates 2 -(p-chlorophenyl)-3-cyano-4-bromo-5-trifluoromethyl pyrrole (Econea) into carboxyl-modified β-cyclodextrin (Econea@CMCD) followed by intercalation into Mg2Al layered double hydroxides (Mg 2Al-Econea@CMCD-LDH), was reported. Powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT -IR) confirmed the incorporation of Econea@CMCD into the galleries of Mg 2Al-LDH. Release tests conducted in 3.5% NaCl solution demonstrated an initial burst release, followed by a slower release rate of Econea (12.3 μ g/cm2· d) compared to that of the pristine Econea coating, indicating favorable control led release behavior. Adhesion experiments using diatoms and mussels showed that Mg 2Al-Econea@CMCD-LDH effectively inhibited the adhesion of typical fouling organisms. Hence, this study presents a practical approach for constructing a controlled release system that involves intercalating neutral and insoluble antifouling agents into LDH interlayers, effectively reducing the waste of antifouling agents and extending the service life of antifouling coatings.

Organic silicone fouling release coatings have attracted attention from countries around the world due to their superior environmental friendliness and long - term effectiveness, and have become an important development direction for ship antifouling materials. In the development of antifouling coatings, formula screening and antifouling performance evaluation are important steps, and the establishment of evaluation methods for f ouling release coatings in marine environments is supported by the failure mechanism.This study conducted a 2 -year real sea immersion test on the fouling release coatings, and systematically obtained the changes in key antifouling characteristic parameters such as coating surface energy, surface chemical groups, and surface roughness over time. The surface roughness and surface energy of the coating gradually increased, while the peak height ratios of methyl -siloxane groups gradually decreased. Through infr ared spectroscopy, Raman spectroscopy, X -ray photoelectron spectroscopy, and MAS NMR analysis, the failure mechanism of organic silicone fouling release coatings in real sea was explored. In seawater environment, the surface methyl of the coating is gradua lly oxidized to methylene, and the silicon element transitions from the Si - (O) 2 state to the inorganic Si - (O) 4 state, gradually becoming inorganic. There is also an adhesion and friction effect between sea sand and marine organisms. Coating failure is mainly caused by the gradual aging (oxidation) and wear of materials in seawater environment, leading to degradation and imbalance of antifouling characteristic parameters. This study provides a new theoretical basis for the performance evaluation of organic silicone fouling release antifouling coatings.

Biofouling formation on the surfaces of ship hulls can bring about some unwanted and detrimental consequences, which has been recognized as a widespread problem. Toxic compounds, such as copp er-based antifoulants, can prevent the happening of biological fouling, but they have negative impacts on non -target organisms and lead to detrimental ecological effects. Environmental concerns and legislation require developing new eco -friendly fouling -resistant technologies to replace toxic antifoulants. Recently, It was found that microtopographies of pillars, triangles/pillars, ridges and Sharklet AFTM could reduce the attachment of Ulva spores and Cobetia marina, and that hierarchical wrinkled surface topographies could resist biological fouling even after 18 months field test. It may be useful in the designing of more powerful antifouling microtopographies if we can correctly predict microbial adhesion on regular microstructures. In this paper, six well-defined microtopographies were applied to prevent N. pinna attachment, and thermodynamic method was used to predict cells adhesion. Diatom attachment assay showed that the cells density was reduced significantly on all microtopographies compared to the smooth surface, and the relative attachment density of N. pinna had a reciprocal -proportional relationship with the free energy of adhesion ( ΔGadh). Historical data also showed that the thermodynamic parameter ΔGadh is reliable to correctly predict Cobetia marina attachment to microtopographies, and the cell relative attachment density has a negative proportional correlation with ΔGadh too. Because thermodynamic approach can be used to calculate ΔGadh for cell attachment to regular and irregular surfaces, it may be widely used to design new antifouling materials.

Marine biofouling significantly impairs maritime vessels, affecting navigation speed and increasing fuel usage. Antifouling coatings, traditionally containing toxic biocides like organotin and DDT, are used to prevent marine organisms from attaching. However, due to environmental concerns, these b iocides are being phased out, prompting the need for eco-friendly alternatives. This investigation builds upon previous studies focusing on phenolic compounds from Ranunculaceae plants and amide compounds from Ulvaceae plants. Using these as templates, a variety of benzamide derivatives were designed to study their antifouling effects. Three structurally similar benzamide compounds, HNOB, DOLPA, and DHNOB, were synthesized, with HNOB showing the best antifouling activity. Structural analysis revealed that t he combination of polar and non -polar elements in these compounds enhanced their antifouling properties.HNOB was chosen as an antifouling ingredient and reacted to form HNOBA, which was then used to create PBNH -Ax copolymers. These copolymers formed films at room temperature with good interlayer adhesion. Experiments showed that HNOB, released through ester hydrolysis, effectively prevented diatom attachment and exhibited antimicrobial properties. This research outlines the synthesis of innovative antifouli ng molecules from natural product derivatives and their integration into polymer chains, demonstrating their potential for marine antifouling applications. Future research should investigate the long-term stability and effectiveness of these materials in r eal marine conditions and their ability to combat a wide range of fouling organisms.

A long-standing quest in marine materials science has been the development of tough and effective antifouling coatings for diverse surface protection. However, most commercial coatings are severely limited by poor mechanical behavior and unsustainable passive biocidal effect, leading to irreversible marine biof ouling and even microbiologically influenced corrosion (MIC). Herein, inspired by the amorphous/crystalline feature within nacreous platelets, we develop a mechanically robust antifouling coating composed of biopolymer -based hydrogel and dense metal - organic frameworks (MOFs). Tailoring the crosslinked networks across multiscale interfaces could furnish strength, dissipate strain, and improve toughness of the building blocks, resulting in a firm and scalable configuration on various substrates regardless of material category and surface topology. The resultant coating as a suitable reservoir exhibits a unique active defensive behavior of intelligent MOF degradation or drug release, enabling a groundbreaking performance for broad - spectrum biofouling and corros ion control. Notably, neither attachment of marine organisms nor MIC of metal substrates is observed and aggravated during the prolonged testing process in complex biological environments. This study should provide distinctive insights into the underlying multimechanisms of comprehensive anti-fouling-corrosion and pioneer a rational strategy to design next-generation reliable MOFs-derived coatings in marine environments.

Marine biofouling is a difficult problem that needs to be faced in the process of developing marine resources. Currently, applying marine anti-fouling coatings is the most economical and effective way to prevent and control marine biofouling. Therefore, coupling agent modified pyrimidine ( PD-560) was prepared by amino epoxide ring opening reaction using silane coupling agent KH560 and 2,4,6 -triaminopyrimidine. Subsequently, pyrimidine modified polyaspartic ester polyurea (AMPU -x) was prepared by PD-560, polyether polyol, isophorone diisocyanate (IPDI) and polyaspartic ester NH1220. The introduction of pyrimidine into AMPU-x makes the coating surface rougher, while the increase in hydrophilic hydroxyl content leads to a more hydrophilic surface. In addition, adding modified pyrimidine can improve the mechanical properties of the coating, but excessive addition can affect the crystallinity inside the polymer and reduce the tensile strength of the coating. The anti-fouling performance of the coating was evaluated through anti -diatom adhesion experiments, and the introduction of pyrimidine significantly increased the anti-fouling performance of the polyurea coating. Among them, AMPU2.5 had the best performance, with an inhibition rate of 93.7% for Halamphora sp. (Ha.) diatom adhesion and 90.3% for Nitzschia Chosterium (Nc.) diatom adhesion after 7 days, indicating that the coating has excellent inhibition performance against primary fouling organisms. The pyrimidine modified polyaspartic ester urea coating with excellent anti fouling performance provides theoretical support for the development of ship protective coatings.

It is an increasingly serious problem that marine biofouling causes hull surface damage and marine biological invasion. Designing a coating with excellent wear resistance and good antifouling performance is a difficult ch allenge. In order to solve this problem, the use of a stain release coating with excellent wear resistance to prevent biological adhesion is an effective strategy. Polydimethylsiloxane (PDMS) has received extensive attention as a antifouling coating for sh ips, but its adhesion and mechanical properties are relatively insufficient. In this study, silicone modified polyaspartic polyurea was prepared by synchronous crosslinking polymerization. Polyaspartate polyurea is used to form a tight cross -linked network with excellent toughness and outstanding adhesion. Polydimethylsiloxane is used to form a softer crosslinking network with lower surface energy and surface elastic modulus. The polyurea and silicone molecular chains are locked to each other through their respective polymerization systems and crosslinking processes to form an interpenetrating polymer network (IPN). The synergistic effect between silicone and polyurea provides excellent mechanical properties and dirt release performance through a locking mec hanism. It provides a promising general strategy for the development of antifouling coatings with excellent wear resistance.

Biofouling poses severe hazards to marine underwater infrastructures and is a key factor in species invasion. The issue of biofouling in freshwater environment s should not be overlooked either, as it disrupts the balance of ecosystems and poses grave threats to human health and the sustainable use of water resources. Although there are similarities in the biofouling process between freshwater and marine environments, especially in the stages of conditioning film formation, biofilm development, microfouling, and macrofouling, there are significant differences in environmental conditions (e.g., pH values, flow velocity), species diversity, and management strategies. In response to this challenge, Hong and colleagues have developed an environmentally friendly underwater anti -fouling metal. This material's controlled release of copper ions is particularly suited for resisting the initial attachment of biofouling. By r eleasing high concentrations of copper ions in microareas on the surface, it inhibits the attachment of proteins and polysaccharides without releasing large amounts of copper ions into the surrounding aquatic environment, reducing the adhesion strength of biofilms and preventing their formation, thereby significantly delaying the progression of biofouling. This technology aims to meet the wide-ranging anti-fouling needs of both freshwater and marine environments, showing broad - spectrum anti-fouling effects in both static and dynamic waters, and is poised to lead the development of the next generation of anti-fouling technology.

Hydrogen embrittlement (HE) has been a challenge for many applications of alloys. Hydrogen (H) absorption causes H accumulation at traps such as grain/phase boundaries, dislocations, and precipitates, leading to microstructural degradation that may lead to cracking under mechanical loading. HE has been studied extensively and many mechanisms have been proposed. However, achieving a fundamental understanding of HE requires real-time information of H infusion and accumulation, as well as the H -microstructure interactions. Previously we utilized synchrotron high - energy XRD (HEXRD) for operando study of HE of a super duplex stainless steel (SDSS) under electrolytic H -charging and tensile loading. The results from a fine - grained SDSS show dynamic heterogen eous microscopic strain evolution in the microstructure, i.e., lattice expansion in the austenite and compression of the ferrite, but no crack formation [1]. However, for a coarse-grained SDSS, th e measurement show H -induced microstructural deformation exc eeding the critical threshold of cleavage cracks in ferrite when the load was rasied to 100% of actual yield strength. Recently, we performed time -of-flight (ToF) neutron imaging of the coarse -grained SDSS during electrolytic H charging under tensile loading, aiming to to investigate the H infusion and microstructure degradation leading to crack formation. The ToF neutron imaging vs. H charging time provides real -time information of H accumulation in the microstructure and deformation damage such as crack i nitiation. The neutron transmision data shows the signal attenuation due to increased H content in the microstrucutre, while the ToF Bragg edge data also holds the potential for the strain evolution of the austenite and ferrite phases (data to be analysed). Here we report real-time observation of the H accumulation in the microstrucutre and the heterogeneous strain evolution in the microstructure, leading to crack formation.

Titanium alloy with excellent all-round properties has been widely used in the manufacture of aircraft engine compressor blades. The surface of titanium alloy blades of aircraft engines serving in marine atmosphere will deposit solid NaCl, which is prone to suffer from hot salt stress corrosion damage. Therefore, it is necessary to investigate effective protection technologies of hot salt stress corrosion of titanium alloy. In this study, the effects of pre -oxidation and plasma electrolytic oxidation on the ho t salt stress corrosion behavior of TC11 titanium alloy at 500° C were investigated by slow strain rate tension testing. The results show that the hot salt stress corrosion sensitivity of pre-oxidized TC11 titanium alloy at 500° C is still high, the oxide film formed during high temperature oxidation cannot resist NaCl well. In addition, this oxide film with certain brittleness is not conducive to the improvement of hot salt stress corrosion resistance. Plasma electrolytic oxidation treatment produces an oute r oxide layer consisting of nanocrystals and amorphous layers and a dense inner amorphous oxide layer on the surface of the TC11 titanium alloy. The outer oxide layer has an inhibiting effect on the hot salt corrosion of TC11 titanium alloy, and the inner amorphous oxide layer effectively prevents the penetration and erosion of the corrosive media Cl and O into the TC11 titanium alloy matrix. The initiation of hot salt stress corrosion cracking is inhibited and the hot salt stress corrosion resistance of TC11 titanium alloy at 500° C is significantly increased.

This study conducted a comprehensive failure analysis of 304 stainless steel pipes used in PBAT (polybutylene adipate -co-terephthalate) production equipment. A leakage in the pipe prompted an investigation into the cause of failure. By comparing the physicochemical properties of the failed pipe with those of a functioning one, this study aimed to identify the reason for pipe failure. The analysis included chemical composition testing, macro and micro fracture observations, metallographic examination, hardness testing, and intergranular corrosion tests. The results indicated that the primary cause of failure was stress corrosion cracking (SCC), with chloride ions (Cl−) acting as the main corrosive agent. Cracks initiated from the inner surface and propagated outward, eventually leading to leakage. This study not only provides insights into the failure mechanisms of stainless steel pipes in PBAT production environments but also suggests preventive measures to avoid similar failures in the future. The findings are significant for ensuring the reliability and safety of PBAT production facilities.

Blending a certain proportion of h ydrogen into natural gas and transporting it through existing pipelines is the most cost -effective method for long -distance hydrogen transportation. However, the evaluation of the adaptability of hydrogen - blended natural gas pipelines is not yet fully deve loped. This study investigates the hydrogen embrittlement behavior of X60 steel under hydrogen blending ratios of 0–30% at 12 MPa using slow strain rate tensile (SSRT) tests combined with SEM analysis. In-situ high-pressure gas-phase hydrogen permeation tests were conducted to accurately determine subsurface hydrogen concentrations under different hydrogen blending ratios. The results indicate that as the hydrogen blending ratio increased from 10% to 20%, the subsurface hydrogen concentration, plasticity lo ss, and hydrogen embrittlement sensitivity significantly increased. Additionally, a positive correlation was observed between subsurface hydrogen concentration and hydrogen embrittlement index. Based on the hydrogen permeation, SSRT results, and fracture m orphology analysis, the safe critical range for the operation of X60 hydrogen-blended natural gas pipelines was determined to be a hydrogen blending ratio of 10%.

Multiphase stainless steel is a novel stainless steel with good mechanical properties, owing to the transformation -induced plasticity (TRIP) effect of retained austenite. We explored the influence of nitrogen alloying on the resist ance to hydrogen-assisted cracking of a novel multiphase stainless steel, aiming to develop a multiphase stainless steel resistant to hydrogen embrittlement. This was accomplished through techniques such as transmission electron microscopy (TEM), electron backscatter diffraction (EBSD), slow strain rate tensile testing (SSRT), and thermal desorption spectroscopy methods (TDS). The results showed that nitrogen alloying decreased the susceptibility of multiphase stainless steel to hydrogen -assisted cracking, resulting in an 8% reduction under the in-situ hydrogen charging condition and a 30% reduction under the pre -hydrogen charging condition. Nitrogen alloying increased the austenite content in multiphase stainless steel, decreased the apparent diffusion coefficient of hydrogen in multiphase stainless steel, and inhibited the diffusion of hydrogen within the material. Additionally, nitrogen alloying enhanced the stability of austenite in multiphase stainless steel, thus delaying the initiation of hydrogen-assisted cracks. Corresponding author: Cuiwei Du, professor at University of Science and Technology Beijing. Her research directions include corrosion in soil environment and microbiologically influenced corrosion. Contact information: 30 Xueyuan Road, Haidia n District, Beijing 100083, China, email address: dcw@ustb.edu.cn.

To reduce the service risk of U75V welded joints, the hydrogen induced stress corrosion cracking (SCC) behaviour and mechanism of U75V welded joints immersed in a 3.5 wt% NaCl/ hygrogenated solution were investigated using the slow strain rate test (SSRT) method and electrochemical measurements. The weld joint (WJ) shows a more negative potential (−0.56 mV) and higher corrosion current density (9.62 × 10−5 A/cm2) than the base metal (BM) due to concentrated residual stress and more boundaries for hydrogen adsorption. Furthermore, the WJ had a considerably high SCC susceptibility (ISSRT = 0.9237) in the hydrogen solution, with an accompanying mechanism of anodic di ssolution and hydrogen erosion. Because of weld hardening, the WJ has a slightly higher strength value (1000.67 MPa) than that of the BM (996.7 MPa) in the air, and the strength and elongation of both the WM and BM significantly decreased after exposure to the NaCl/ hydrogen solution, particularly for the WJ. These results were mainly attributed to the synergetic effect of stress concentration and micro-galvanic corrosion. We believe that this finding will facilitate the further application of U75V welded joints in steel rails.

Cathodic protection is commonly used for corrosion prevention of duplex stainless steel components in marine environments [1]. However, hydrogen evolution due to cathodic polarization tends to induce hydrogen embrittlement in duplex stainless steel [2]. In this regard, we employed in-situ cathodic protection slow strain rate tensile testing [3] to investigate the mechanical property degradation behavior of duplex stainless steel under different cathodic potentials. Moreover, microscopic characterization methods such as electron backscatter diffraction and theoretical models were employed to rev eal the microscopic mechanism of hydrogen -induced mechanical properties degradation and the changes in fracture mode. Microstructural characterization and statistics of interrupted specimens revealed that hydrogen promoted the growth of voids along ferrite blocks. The increases in the misorientation and density of subgrain boundaries near the voids indicated that hydrogen -induced void growth was related to hydrogen -enhanced plastic deformation, as hydrogen can lower dislocation line energy and surface energ y, thereby facilitating the emission of dislocations from void surfaces and subsequently reducing the critical stress for void growth, according to the established theoretical model of void growth, which was further supported by that the distribution of geometrically necessary dislocation density near the void fits well with the theoretical model.

Four different levels of Cr-series low-alloy high-strength steels (0 wt%, 1 wt%, 2 wt%, 3 wt%) were prepared by vacuum melting and hot rolling, and the stress corrosion (SCC) behavior of four steels was investigated by slow rate tensile (SSRT) and U -bend i mmersion tests. The results show that in the simulated marine atmospheric environment, The addition of 3 wt% Cr inhibits the anodic dissolution(AD) of the matrix and Improves SCC resistance by about 5%. However, in the SO 2- simulated marine atmosphere environment, The addition of 3% Cr increases the SCC sensitivity of the steel by about 60% . The reason for this result is that the hydrogen embrittlement (HE) is gradually dominating due to the high concentration of H ions in this environment, while the addition of Cr significantly increases the strength of the steel and the sensitivity of large angle grain boundaries (HAGB). As the sensitivity of steel to H increases, the sensitivity to SCC increases.

High temperature molten salt reactor is one of the fourth generation reactors, the structure material of which is GH3535 superalloy. GH3535 alloy is subjected to molten salt corrosion and local stresses, so the alloy may crack during service. This will affect the service life of the alloy and the safety of reactor operation. Therefore, the mechanical behavior evolution and mechanism of GH3535 alloy in the molten salt need to be clarified. The creep deformation and fracture behavior of GH3535 alloy under different stress (190MPa, 235Mpa and 270MPa) in 700 oC molten salt and Ar environments was investigated. The minimum creep rate in molten salt is larger than that in Ar and the creep rupture life is shorter in molten salt than that in Ar. Furthermore, under the stress lower than the 220 MPa yield strength, the alloy creep fracture life and elongation in molten salt are both significantly lower than that in Ar. The alloys exhibit a combination of ductile overload and intergranular fracture in both environments, intergranular cracks are formed on the surface and inside of the alloy, but the crack density and depth are larger in the molten salt. In both environments, the processing layer on the surface of the alloy is tempered and recrystallized at 700 oC form a fine crystal layer. The deformation area below the fine crystal layer first cracks initiation under the stresses and expands to the alloy matrix. However, due to the corrosion of the molten salt, Cr loss occurs on the surface of the fine crystal layer, thus connecting with the cracks in the lower layer to form a penetrating crack. The entry of molten salt into the cracks, causing more cracks to form and the elements along the cracks to diffuse to the alloy surface, crack propagation depth is also deeper.

Stress corrosion cracking (SCC) of high strength aluminum alloys is controlled by many factors, including the anodic dissolution, the corrosion -induced hydrogen, and the stress related processes. In the present work, a quantitative estimation of these factors in triggering the SCC of 2024-T351, 7075-T651, and 7050- T6 aluminum alloys in solution and thin electrolyte layer (TEL) in the presence of Cl - and HSO 3- is conducted. It is found that s ynergistic effect of stress, corrosion, and hydrogen during in -situ tensile test dominates the degradation of aluminum alloys in solution environment, while the corrosion -induced hydrogen during exposure without load controls the SCC of aluminum alloys in TEL environment in the presence of Cl -. The former contributes to 96% of total elongation loss of 7075 -T651 and the latter accounts for 78% of the ductility degradation of 2024-T351. In the presence of HSO3-, the contribution of hydrogen-induced degradation further increases and the irreversible damage caused by corrosion shows little effect of the ductility of the 7050 -T6 high-strength aluminum alloy.

Hydrogen-induced delayed cracking (HIDC) represents a significant threat to the dependable performance of automotive steel. In this study, in-situ hydrogen charging constant load tensile tests were employed to measure the critical conditions for HIDC. The threshold stress values were obtained through the relationship between applied stress and fracture time, as illustrated in Fig. 1 a. The assessment of the saf e service area was determined by observing whether fracture occurs in the specimens within the specified time of 200 h, as shown in Fig. 1b. The objective of this work is to measure the specific critical conditions for HIDC of DP1180 steel plate [1] and establish the relationship between pre -strain, threshold stress, and critical hydrogen concentration, as shown in Fig. 1c. Additionally, we also measured the critical conditions for HIDC of another QP1180 steel plate [2] and investigated the effect s of microstructure hydrogen distribution characteristics on HIDC [ 3-5]. T hese findings provide valuable references for the safety asses sment of high -strength automotive steels in hydrogen-exposed environments. Fig. 1 (a) Relationship between applied stress and f racture time. (b) Relationship between applied stress and hydrogen concentration of the broken and unbroke n specimens. (c) Relationship between the pre-strain, threshold stress, and critical hydrogen concentration.

Stress corrosion cracking (SCC) poses a significant threat to the safe operation of stainless steel components in critical engineering fields such as nuclear power, petrochemicals, aerospace, and marine vessels. Due to the complexity of its mechanisms and the numerous influencing factors, effective prevention and control of SCC remain challenging. As a result, the mechanisms, diagnostics, and assess ment of stress corrosion in stainless steel have long been areas of extensive focus in both industry and academia. SCC in stainless steel is an interactive process involving fracture behavior, passive film failure, and electrochemical behavior. Detailed analysis of failure cases, identification of occurrence patterns, and examination of the primary mechanisms and internal and external microstructural influences are crucial for advancing monitoring, detection, and prevention technologies for SCC. This study summarizes the research progress of our team in understanding the microstructural characteristics and monitoring methods for typical stainless steel SCC failures. Our findings indicate that the SCC behavior of stainless steel aligns with a non-steady-state electrochemical model, with the corrosion fracture mechanism being controlled by a mixed mode of anodic dissolution and hydrogen embrittlement. Furthermore, various precipitates and deformation structures resulting from processes such as cold deformation, sensitization, and heat treatment significantly influence the initiation of SCC. The study elucidates the detailed mechanisms and patterns of these effects. These insights not only enhance the understanding of the mechanisms underlying stainless steel SCC but also provide valuable guidance for preventing SCC and optimizing the corrosion resistance of stainless steel, offering both scientific and practical significance.

Corrosion fatigue is one of the important reasons for the rapid failure of engineering structures in marine engineering, rail transit, nuclear industry, etc. To reveal the corrosion fatigue damage mechanism and propose targeted protection methods, the key is to study the damage evolution behavior in corrosion fatigue failure process. However, due to the existence of corrosive media, the evolution behavior of pitting and cracking during corrosion fatigue cannot be obtained by the commonly used two-dimensional destructive characterization methods. How to obtain the spatio - temporal evolution law of corrosion fatigue surface pits and internal cracks in situ and visually has become one of the important challenges to be solved in the field of corrosion fatigue. Therefore, based on the advanced scientific device of light source, this project developed an in -situ corrosion fatigue testing machine compatible with synchrotron radiation imaging line station. The in -situ corrosion fatigue experiment of 7050 high-strength aluminum alloy was carried out, and the space -time evolution law of pitting and cracking during corrosion fatigue was obtained. Several main growth modes of pitting were clarified, and the relationship between the growth rate of corrosion fatigue crack and the range of stress intensity factor was established.

Using selective laser melting (SLM) and hot isostatic pressing (HIP) techniques, the Ni50Co20Cr10Al15Ti2 complex concentrated alloy (CCA) was fabricated. Subsequent investigation into high -temperature oxidation revealed a significant decrease in the ductility of the CCA. To address this issue, measures were taken to regulate t he alloy composition, aiming to prevent the formation of depleted zones during oxidation. This approach successfully enhanced the mechanical performance of the CCA under high-temperature service conditions. After 2000 hours of oxidation at 700° C, the CCA exhibited a dramatic 62.4% reduction in elongation. In contrast, specimens subjected to 2000 hours of aging treatment at the same temperature showed no significant alteration in elongation. Selective oxidation of CCA, particularly targeting the L12 phase, o ccurs at elevated temperatures, leading to the depletion of L12 particles near the oxide layer and the formation of depleted zones. This phenomenon substantially diminishes the anchoring effect of the HEAs/CCAs, facilitating the rapid propagation of intergranular oxidation cracks. The absence of the L12 phase results in a significant decrease in the tensile strength of the depleted zone, suggesting that oxidized CCA exhibits a propensity for abrupt loss of ductility under relatively low strains, culminating in brittle fracture rather than undergoing significant plastic deformation. Utilizing advanced techniques such as ECCI and HRDIC, we observed and analyzed the expansion and internal tearing of oxidation cracks within the depleted zone with precision and c larity. Simulation outcomes highlight the exacerbation of stress concentration at crack tips within the metal matrix in the presence of depleted zones, significantly contributing to the propensity for brittle fracture in the material. To address these chal lenges, we propose an optimized solution focused on the composition of the L12 phase to mitigate selective oxidation at high temperatures. By preventing the formation of depleted zones, this strategy aims to preserve the ductility of CCA under high-temperature conditions, thereby enhancing its mechanical integrity and longevity.

The effect of aging precipitation on the stress corrosion crac king (SCC) mechanism of Ni(Fe, Al) -maraging steel was studied through comparative characterizations and analyses on microstructures and fracture features of the solid - solution and peak -aged steels. Aging precipitation brings a chain of impacts on the deformative compatibility and electrochemical difference between the matrix and other phases or interfaces. The strength of the martensite matrix is enhanced by the abundant and evenly dispersed Ni(Fe, Al) precipitate, thereby reducing the possibility of splitt ing across the martensite laths. Meanwhile, the Volta potential difference between the matrix and the primary NbC particles is increased from 11.3mV to 18.60mV. Since most of the primary NbC particles tend to be distributed along high - angle grain boundaries (HAGBs), the anodic dissolution along HAGBs is accelerated. Therefore, both the mechanical and electrochemical factors, triggered by aging precipitation, are involved in the variation of SCC behavior and mechanism. The SCC susceptibility of the steel is increased along with the increasing tendency of intergranular cracking.

The incompatibility between coolant and structural materials poses a critical challenge to the deployment of advanced Lead -cooled fast reactors. The long -term operational performance of T91 steel in Lead-Bismuth Eutectic (LBE)-cooled reactors is critically impacted by creep deformation and the integrity of protective oxide scales. The present study investigates the creep-to-rupture behavior of T91 steel in static LBE, focusing on the effects of cyclic thermal conditions and oxygen levels. The results demonstrate that cyclic thermal conditions, oxygen deficiency, and elevated stress levels accelerate creep deformation, significantly reducing the creep-to-rupture lifetime of T91 steel. While the protective oxide scale delays crack initiation and propagation by isolating LBE from the steel surface, its integrity is compromised under thermal cycling and low oxygen environments, leading to premature failure. Microstr uctural analyses reveal the mechanisms of oxide scale damage and self -healing, which are essential in understanding the material’s long -term performance. These findings underscore the need to account for oxide scale integrity and its failure mechanisms when designing and evaluating the operational longevity of advanced LBE -based reactors. The study offers valuable insights into improving the safety and durability of structural materials in next-generation nuclear systems.

Stress corrosion susceptibility of 17-4PH martensitic precipitation hardening stainless steel commonly used on offshore platforms was studied by slow strain rate tensile experiments, through which some data such as fracture time, tensile strength, elongation to fracture, and reduction in area were obtained at room temperature in air, and at room temperature, 40 °C, and 70 °C in 3.5% NaCl aqueous solutions. The fracture surface s of the sample s were observed by scanning electron microscope. Three methods in view of ratio, stress corrosion susceptibility index (ISSRT) and fractured surface analysis were employed in or der to analyze and verify s tress corrosion susceptibility of experimental material at different temperatures. The results showed that the experimental material ha s no stress corrosion susceptibility in 3.5% NaCl aqueous solution at room temperature and 40 °C; the susceptibility of the experimental material to stress corrosion is existent but not significant in 3.5% NaCl aqueous solution at 70 °C; stress corrosion leads to the deterioration of mechanical properties of the experimental material with selectivity, and the analytic results would provide reference for its engineering application.