The evaluation of the repassivation tendency of Cr-Mn and Cr-Ni steels using scratch technique

Investigation of the repassivation of Cr-Mn and Cr-Ni steels in sodium sulphate-sodium chloride solution mixture was carried out using scratch testing. The effect of nitrogen in such steels on the pitting and repassivation tendencies was also demonstrated. The effects were compared with pure iron and Fe-N model alloy. The results indicate that the enrichment of nitrogen at the metal/oxide interface was responsible for a higher repassivation capability and a higher localized corrosion resistance of these nitrogen containing Cr-Mn and Cr-Ni steels.