Corrosion behaviour of low temperature plasma carburised 316L stainless steel in chloride containing solutions.

The electrochemical corrosion behaviour of the carburised (expanded austenite) layer on 316L austenitic stainless steel produced by low temperature plasma carburising has been studied in 0.5 MNaCl and 0.5 M HCl + 0.5 M NaCl solutions. The present work focuses on the variation of the corrosion behaviour of the carburised layer with depth from the surface and the effect of carbon concentration on electrochemical behaviour. The results show that the carburised layer has excellent resistance to localised corrosion. There exists a critical carbon concentration, above which the expanded austenite possesses excellent resistance to both metastable pit formation and pit growth.