Characterization of the Passive Film and Corrosion of Martensitic AM355 Stainless Steel |
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| Authors: | Cheng Man Jianxiong Liang Kui Xiao Qiang Yu Xiaogang Li |
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| Affiliation: | 1. Corrosion and Protection Center, University of Science and Technology Beijing, Beijing, China;2. Institute for Special Steel Central, Iron and Steel Research Institute, Beijing, China;3. Institute for Special Steel Central, Iron and Steel Research Institute, Beijing, China;4. Institute of Materials Technology, Ningbo Institute of Material Technology &5. Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, China |
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| Abstract: | Electrochemistry methods were used to investigate the influence of pH on the passive film and corrosion behavior of ultrahigh strength AM355 stainless steel in chloride-containing media. Analysis of the Pourbaix diagram indicates that AM355 stainless steel exhibits higher corrosion resistance in natural and near-natural environments than that in acidic and alkaline conditions. Electrochemistry measurements and composition analysis of the passive film show that pitting potential increased due to the enhanced repassivation capacity of AM355 stainless steel with increasing pH. The mixed MnS/oxide inclusions are the main pitting sensitive locations under all conditions. Morphological observations and energy-dispersive spectroscopy showed that the influence of the gap between the martensitic laths is significant with increasing pH. The inclusions, element concentrations, and microstructures weaken the resistance of ultrahigh-strength martensitic AM355 stainless steel against corrosion. |
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| Keywords: | Electrochemistry inclusion passive film pitting corrosion ultrahigh-strength martensitic stainless steel |
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