Wear behaviour of UHMWPE against DC-pulsed plasma nitrided and duplex treated AISI 316L used in hip joint replacements

Wear behaviour of the artificial joint replacements plays a critical role in implant failure. The UHMWPE-AISI 316L tribological system, widely used on joint prostheses, was studied. Two surface modifications were applied to the stainless steel counterface: DC-pulsed plasma nitriding and duplex (DC-pulsed plasma nitriding + TiN coating by cathodic-arc evaporation) treatments. An Amsler Disc Machine Type A-135 was used as an approximation to real loading conditions. Worn surfaces, weight loss curves and wear debris were analysed. The results show that the nitriding and duplex treatments improve the wear resistance of the tribological system. Different types of damages were observed on the UHMWPE worn surfaces depending on the surface treatment of the stainless steel.