The High-Temperature Corrosion of Austenitic Stainless Steel with a NaCl Deposit at 850°C

Three austenitic Fe–Cr–Ni alloys (253MA, 310SS and 353MA) coated with 2 mg/cm² NaCl were oxidized at 850°C in a slow airflow. The results indicate that the initial NaCl coating accelerated oxidation of alloys by oxychloridation and chloridation/oxygen-substitution cyclic reactions, resulting in the formation of a thick scale and an interconnecting void network in the substrate. Voids were tunnels in shape. Some were filled with corrosion products, and some corrosion products formed on the walls of the voids. The thickness of metal loss was related to the consumption of both chromium and iron in the alloy substrate. In this study, 310SS had better corrosion resistance after 36 hr exposure, followed by 353MA, and the worst was 253MA.