Corrosion and tribocorrosion behavior of Ti6Al4V/xTiN composites for biomedical applications

The corrosion and tribocorrosion behavior of Ti6Al4V/xTiN (x=0, 5, 10 and 15, vol.%) composites fabricated by solid-state sintering and their relationship with the microstructure and microhardness were investigated. Simulated body conditions such as a temperature of 37 °C and a simulated body fluid were used. The main results demonstrated a microstructural change caused by the α-Ti stabilization due to solid-solution of nitrogen (N) into the titanium (Ti) lattice, producing a maximum hardening effect up to 109% for the Ti64 matrix by using 15 vol.% TiN. Corrosion potentials of composites changed to more noble values with the TiN particle addition, while corrosion current density of samples increased as an effect of the remaining porosity, decreasing the corrosion resistance of materials. However, changes to a less passive behavior were observed for samples with 15 vol.% TiN. The non-passive behavior of composites resulted in the reduction of the potential drops during rubbing in tribocorrosion tests. Besides, an improvement of up to 88% of the wear rate of composites was seen from the solid-solution hardening. The results allowed to understand the relationship between composition and sintering parameters with the improved tribocorrosion performance of materials.