engleski

Influence of nitriding on corrosion resistance of martensitic X17CrNi16-2 stainless steel

Stainless steels are widely used due to their corrosion resistance, but low wear resistance limits their industrial application. Nitriding increases surface hardness and improves wear resistance. However, nitriding can sometimes reduce the corrosion resistance of stainless steels due to CrN precipitation. In this paper, the influence of nitriding on the corrosion resistance of martensitic stainless steel was investigated. Plasma nitriding at 440°C and 525°C and salt bath nitrocarburizing were carried out on the martensitic X17CrNi16-2 stainless steel. Microhardness profiles of the obtained nitrided layers were examined. Corrosion behaviour of samples was evaluated by immersion test in 1 % HCl and by electrochemical corrosion tests performed in 3.5 % NaCl. Results show that salt bath nitrocarburizing, as well as plasma nitriding at low temperature, increased microhardness without reducing corrosion resistance. On the other hand, plasma nitriding at a higher temperature reduced the passivity of the martensitic steel and increased the corrosion tendency.

martensitic stainless steel; salt bath nitrocarburizing; plasma nitriding; corrosion resistance

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