OXIDATION OF STAINLESS-STEELS (AISI-304 AND AISI-316) AT HIGH-TEMPERATURE - INFLUENCE ON THE METALLIC SUBSTRATUM

Stainless steels of type AISI 304 and 316 were heated in air (1-5-15 minutes at 900-1000-1100-degrees-C) and the oxide layers formed on the surface were analyzed by XRD, CEMS, SIMS and FTIR. At these temperatures the main oxides are Cr2O3 and a spinel close to MnCr2O4 for polishing samples (with Fe2O3 for the chemically cleaned samples). The oxidation induces a Cr and Mn depletion from the metallic substratum and a phase transformation gamma (f.c.c.) --> alpha (b.c.c.) in a thin layer of the steels near the oxides - metal interface.