The surface characterization and passive behavior of Type 316L stainless steel in H₂S-containing conditions

Highlights: • The corrosion behavior of 316L at various anodic potentials was studied. • The enrichment of Ni in the passive film is found. • The oxidization degree analysis indicates metallic elements are incompletely oxidized in the film. • The higher atom ratio of S to the anionic elements at higher potentials is responsible for the passive film degradation. - Abstract: The protectiveness and characterization of passive films formed at various potentials in H₂S-containing environments were studied using electrochemical measurements and surface analysis method. The corrosion resistance of 316L in H₂S-containing environment decreases with the applied potential. The Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) results indicate that Ni participates in the film formation, which results in the corresponding enrichment in the passive film. The oxidization degree analysis indicates that metallic elements are present in the passive film. Sulfide ions are significantly favored in the passive film at higher potentials, which is responsible for the breakdown of passive film.