High Temperature Corrosion Behavior of Inconel Alloy 740H in Simulated Coal-Ash / Flue-Gas Environment at 850° C

摘要

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.