CORROSION PERFORMANCE OF ALUMINA SCALES IN COAL-GASIFICATION ENVIRONMENTS

Corrosion of metallic structural materials in complex gas environments of coal gasification is a potential problem. The corrosion process is dictated by concentrations of two key constituents: sulfur as H2S and Cl as HCl. This paper examines the corrosion performance of alumina s cales that are thermally grown on Fe-base alloys during exposure to O/ S mixed-gas environments. The results are compared with the performanc e of chromia-forming alloys in similar environments. The paper also di scusses the available information on corrosion performance of alloys w hose surfaces were enriched with Al by the pack-diffusion process, by the electrospark deposition process, or by weld overlay techniques.