Influences of pH value, temperature, chloride ions and sulfide ions on the corrosion behaviors of 316L stainless steel in the simulated cathodic environment of proton exchange membrane fuel cell

• 316L stainless steel is in the passive state in H2SO4 solution.
• The passivity is enhanced with the increased pH value, decreased temperature, chloride and sulfide ions.
• The passive film on 316L SS is modeled as a p-n heterojunction.
• The donor and acceptor densities increase with increasing temperature, chloride ions, sulfide ions and decreasing pH value.

316L stainless steel is in the passive state in a simulated cathodic environment, and the passivity of 316L SS is enhanced with increasing pH value, decreasing temperature, decreasing chloride ions and sulfide ions concentrations. Mott–Schottky plots show that the passive films appear a p-n heterojunction, and the donor and acceptor densities reach 1022 cm−3, showing a highly defective character of the passive film. The donor and acceptor densities increase with increasing temperature, increasing chloride ions and sulfide ions concentrations, while they decreased with increasing pH value. The decreased passivity and the increased doping density may be beneficial to the conductivity of the passive film, but they adversely affect the protectiveness of the passive film toward corrosion.