Atomic origin of CO2-promoted oxidation dynamics of chromia-forming alloys
作者
单位
1School of Materials Science and Engineering、Xiangtan University、Xiangtan 411105、China 2Clean Nano Energy Center、State Key Laboratory of Metastable Materials Science and Technology、Yanshan University、Qinhuangdao 066000、China 3Department of Mechanical Engineering & Materials Science and Engineering、Program、State University of New York、Binghamton、NY 13902、USA
关键词
收录来源
International Corrosion Congress · 第22届国际腐蚀大会
摘要
The development of atomic imperfections within oxide films from high - temperature oxidation of heat-resistant alloys significantly limits the self-protectiveness of the surface oxide, contributing t o the failure of energy generating system components such as turbines, engines, and heat exchanges. Directly probing the dynamics of such atomic defects is challenging because of the extreme thermochemical conditions of high -temperature oxidation. Using en vironmental transmission electron microscopy observations, here we directly capture atomic-scale dynamics of vacancies in growing Cr2O3 film during high-temperature oxidation of NiCr alloy in CO 2. Coordinated with theory modeling, we delineate the atomisti c mechanisms associated with the effect of interstitial carbon derived from CO 2 on promoting the formation, migration and clustering of atomic vacancies to result in the enhanced alloy oxidation. The identified oxidation mechanism can find broader applicability in utilizing the atmosphere to tune the formation and evolution of atomic - scale defects, thereby affecting the mass transport properties of the growing oxide film.