Low energy SIMS characterization of passive oxide films formed on a low-nickel stainless steel in alkaline media

Low-energy secondary ion mass spectrometry (SIMS) was used to study the oxide films formed on a low-nickel austenitic stainless steel (SS), potential replacement to conventional AISI 304 SS in reinforced concrete structures (RCS) that are subjected to aggressive environments. The effect of carbonation and the presence of chloride ions were studied. The oxide films formed a chemically gradated bi-layer structure with an outer layer predominately constituted by iron oxides and an inner layer enriched in chromium oxides. Chloride ions were not found in the oxide film but did have an effect on film structure and thickness.