Effect of cold deformation on the electrochemical behaviour of 304L stainless steel in contaminated sulfuric acid environment

• Published in: Applied surface science 2017-12, Vol.425, p.628-638
• Main Authors: Luo, Hong, Su, Huaizhi, Ying, Guobing, Dong, Chaofang, Li, Xiaogang
• Format: Article
• Language: English
• Subjects: Bipolar plate; Cold deformation; Stainless steel; Sulfuric acid
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2017.07.057

[Display omitted] •Microstructural characterization of 304L stainless steel was investigated during cold deformation.•Cold deformation increased the dissolution rate of the passive film.•The Cr/Fe and O2−/OH− ratios in the passive film decreased with an increase in the cold deformation level.•Corrosion resistance of 304L stainless steel was found to be affected by the cold deformation. The effect of cold deformation on the microstructure and electrochemical corrosion behaviour of 304L stainless steel in contaminated sulfuric acid solutions (simulated proton exchange membrane fuel cells environments) were evaluated using electron backscatter diffraction analyses, electrochemical measurements, and surface analyses. The internal microstructure,including the grain sizes, angles of the grain boundaries, low coincidence site lattice boundaries, and phase transformations, was changed due to the cold deformation. No noticeable modifications of the pitting corrosion potential were observed during the various deformations, except for a slight enhancement in the passive current density with an increase in the deformation. The CrO3 and metal Ni species in the passive film were investigated after deformation. After heavy deformation (greater than 60%), nickel oxides were detected. Moreover, the Cr/Fe and O2−/OH− ratios in the passive film were higher before deformation, and they decreased with an increase in the deformation level.