Combined effect of TiN coating and surface texture on corrosion-wear behavior of selective laser melted CP-titanium in simulated body fluid

The present work reports a facile surface modification method to improve the tribological performances of selective laser melting (SLM) manufactured titanium parts. Commercial pure titanium samples with the textured surface of different texture density were designed and prepared in a single step by SLM, followed by heat treatment in N2. The microstructures, mechanical properties as well as the corrosive and tribological performances in the simulated body fluid of the samples were studied. Results showed that the generated nitride coating significantly improved the surface hardness from 5.2 to 13.3 GPa. The frictional coefficient of nitride coating decreased from 0.36 to 0.28, and more importantly, the wear rate of the coating was reduced by more than 20 times, comparing with the sample without coating. The surface texture further decreased the frictional coefficient. The samples without nitride coating exhibited typical adhesive wear, while the surface texture reduced the adhesive wear of the samples effectively. On the other hand, the wear mechanism of the nitride coating was intergranular brittle peeling under the combination of corrosion and friction, but surface texture restrained the propagation of cracks on the surface.