A comparative study of corrosion behavior of S-phase with AISI 304 austenitic stainless steel in H2S/CO2/Cl- media

S-phase was introduced on stainless steel surface by low-temperature liquid oxy-nitriding and its influence on the corrosion behavior has been explored through surface analysis and weight-loss method. The results indicated that the S-phase layer can significantly improve the corrosion resistance of austenitic stainless steels in H2S/CO2/ Cl- simulated solutions, which was proved by lower corrosion rate, surface, and cross-sectional topography after corrosion. This improvement can be attributed to the fact that the Fe3O4 layer blocking the sulfur-containing medium and the consumption of H+ by the active nitrogen atoms, making it difficult for the corrosive medium to penetrate the steel.