STEM Characterization of Metal Dusting Corrosion in Ni-based Alloy 600 and Fe-based Alloy 800H Exposed to a High Pressure Environment

Metal dusting corrosion is a severe failure mechanism in metallic materials in the petrochemical industry. This form of degradation typically occurs when alloys expose to reducing gaseous environments (CO, H2, CO2, H2O, and CH4) with and high carbon activity (ac > 1) at a median temperature range (400 -800 o C). Formation of graphite, carbides, and metal dusts on alloys significantly damage the working components. The early establishment of continuous Al2O3 scales on the alloy surface can limit graphite nucleation or/and impede inward diffusion of carbon Coupled with this are several recent studies which have shown that susceptibility to metal dusting tends to be much greater under high-pressure exposure conditions Despite the practical importance, studies of metal dusting mechanisms and strategies for improving dusting resistance under pressurized environments are still very limited.