Enhanced corrosion resistance and wear resistance of duplex stainless steel processed by shot-peening combined with electrochemical nitriding

To improve the wear resistance and anticorrosion property of duplex stainless steel (DSS), surface treatment combining high-energy shot-peening (HESP) and electrochemical nitriding was applied to DSS. The strong nitride peak detected through X-ray photoelectron spectroscopy indicated that HESP pretreatment accelerated the electrochemical nitriding process. The treatments improved the microhardness of DSS from 242 HV(100g) to 450 HV(100g) and the wear resistance of DSS was considerably enhanced. Electrochemical tests revealed that HESP pretreatment improved the passivation ability of the nitriding layer of DSS in the borate buffer and 3.5 wt-% NaCl solutions. The greater corrosion resistance of the nitriding layer was attributed to the passive film with lower a number of structural defects. The nitriding layer on the HESP-pretreated DSS showed good corrosion resistance in the 3.5 wt-% NaCl solution.