Influence of nitrogen on corrosion behaviour of high nitrogen martensitic stainless steels manufactured by pressurized metallurgy

Abstract

Effect of nitrogen on microstructure and corrosion behaviour of high nitrogen martensitic stainless steels manufactured by pressurized metallurgy was investigated by microscopy, electrochemical and spectroscopy analyses. Results indicated that increasing nitrogen content significantly enhanced the corrosion properties of martensitic stainless steels, while excess nitrogen deteriorated the corrosion resistance. The impacts of increased nitrogen content could be summarized as three aspects: the change of precipitation content and conversion of main precipitates from M23C6 to M2N; the enhanced protection performance of passive film by enrichment of Cr, especially Cr2O3 and CrN; the improved repassivation ability by increased nitrogen content in solid solution.