Corrosion behaviour of austenitic stainless steels in carbonate melt at 923 K under controlled CO2-O2 environment

Highlights: • Corrosion study of austenitic stainless steels in carbonate melt for high temperature concentrated solar power (CSP) application. • Corrosion behaviour of type 310S, type 316L and type 304 stainless steel is different from each other. • Metallic fragments are present in the corrosion layer of stainless steel; and on increasing Ni content in the substrate the fragmentation is suppressed. • Corrosion resistance in decreasing order: type 310S >> 316L > 304 stainless steel. - Abstract: Corrosion behaviour of austenitic stainless steels (SS) was studied in carbonate melt for high temperature solar thermal systems. Corrosion resistance of type 310S, 316L and 304 SS is different from each other and increases with increasing Cr and Ni content in the substrate. 310S SS is significantly ennobled in the melt as compared to 316L SS or 304 SS. Corrosion process of SS in the carbonate melt is a mixed control of both anodic and cathodic reactions. Metallic fragments from the substrate are incorporated in the corrosion layer and the degree of incorporation is different for each SS.