The effects of graphene oxide doping on the friction and wear properties of TiN bioinert ceramic coatings prepared using wide-band laser cladding

Abstract

In this study, aiming to improve the tribological properties of TiN ceramic coatings, the effects of different pairs of sliding balls on the coatings during wear were investigated, which guided the application of the TiN coatings. Using the wide-band laser cladding technique, TiN bioinert ceramic coatings doped with graphene oxide (GO) nanosheets as self-lubricating phases were prepared on Ti6Al4V. The GO doping did not change the main phase compositions of the coating and made an improvement in the coating quality. GO doping significantly affected the wear resistance of the coating and effectively reduced its friction coefficient. When the coating was sliding against Si3N4, GO doping slightly reduced the wear resistance of the coating; while the coating was sliding against Ti6Al4V alloy and ultrahigh molecular weight polyethylene (UHMWPE), respectively, GO doping significantly improved the wear resistance of the coating. When the doping amount of GO was 3 wt%, the friction coefficients of the coating during sliding against the three material kinds decreased the most: 22 %, 17 %, and 25 % for the Si3N4, Ti6Al4V, and UHMWPE, respectively. Both oxidation wear and abrasive wear were observed when the GO-doped TiN self-lubricating ceramic coatings sliding against Si3N4 balls, Ti6Al4V balls and UHMWPE balls, and fatigue wear was also observed when the coating sliding against Si3N4 balls. The primary antifriction mechanism of the GO-doped TiN ceramic coating during sliding against Si3N4 balls was that the GO in the coating was exposed to the sliding surface to form a lubricating film. It is feasible to apply GO-doped TiN bioinert ceramic coating to artificial joint.