A comparative study on the corrosion behavior of CoCrNi medium-entropy alloy and 316L stainless steel in simulated marine environment

• Published in: Intermetallics Vol. 139; p. 107370
• Main Authors: Zhu, Min, He, Feng, Yuan, Yongfeng, Guo, Shaoyi, Wei, Guoying
• Format: Journal Article
• Language: English
• Published: Barking Elsevier Ltd 01-12-2021; Elsevier BV
• Subjects: Alloys; Anodic dissolution; Austenitic stainless steels; Cathodic dissolution; Comparative studies; Corrosion behavior; Corrosion prevention; Corrosion resistance; Corrosion resistant alloys; Corrosion tests; Dissolution; Entropy; Galvanic corrosion; Immersion tests (corrosion); Marine environment; Marine technology; MEA; Medium entropy alloys; Nonmetallic inclusions; Oxide inclusion; Passive film; Stainless steel; Surface analysis (chemical); Technology assessment; MEA; Oxide inclusion; Passive film; Corrosion behavior
• ISSN: 0966-9795; 1879-0216
• DOI: 10.1016/j.intermet.2021.107370

This paper investigates the difference in the corrosion resistance and passive property of CoCrNi medium-entropy alloy and 316 L stainless steel in a simulated marine environment by using electrochemical measurements, immersion test and surface analysis technology. The results reveal that CoCrNi MEA has more superior anti-corrosion resistance than that of 316 L. The difference in the corrosion resistance is related to the microstructure and surface passive film. Due to the presence of oxide inclusion, micro-galvanic corrosion is formed between the oxide inclusion and CoCrNi matrix, which promotes the anodic dissolution of CoCrNi MEA and induces the formation of pits. The matrix as the anode mainly undergoes the selective dissolution of Co element, while the selective dissolution of Co and Ni elements is occurred in the cathodic oxide inclusion.
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•In 3.5%NaCl solution, the corrosion resistance of CoCrNi MEA is better than that of 316 L.•Anti-corrosion property of MEA and 316 L is associated with grain size, oxide and passive film.•Micro-galvanic corrosion effect between oxide and matrix facilitates the corrosion of MEA.•Pits on MEA are mainly attributed to the dissolution of Co element.•Inclusion as cathode occurs the selective dissolution of Co and Ni elements.