Plasma nitriding of AISI 2205 steel: Effects of surface mechanical attrition treatment and chemical etching

Abstract

In the present study, surface mechanical attrition treatment (SMAT) and plasma nitriding were conducted on AISI 2205 steel. SMAT was effective in enhancing the surface hardness of the steel by about 80%. The influence of SMAT on the corrosion behaviour of the steel was studied in a 3.5 wt-% NaCl solution. Due to the stable and thicker passive layer, improved corrosion resistance was observed for the SMATed steel. However, nitrogen diffusion during plasma nitriding was impeded by the improved passivation, especially for the lower duration (30 min) of chemical etching/cleaning (i.e. sputter cleaning in hydrogen plasma) of the specimen's surface. Furthermore, high chemical etching duration (120 min) resulted in improved surface hardness and nitriding kinetics. © 2016 Institute of Materials, Minerals and Mining.