Mechanical, in-vitro corrosion, and tribological characteristics of TiN coating produced by cathodic arc physical vapor deposition on Ti20Nb13Zr alloy for biomedical applications

Although Ti-based alloys have shown improved biocompatibility, the release of metal ions at long implantation times due to reduced surface hardness and wear resistance results in reduced service lifetimes of implants and cause implant loosening. To overcome these limitations and extend the lifetime of Ti-based implants, a TiN ceramic coating was deposited on the developed Ti20Nb13Zr (TNZ) alloy by using cathodic arc physical vapor deposition. The objective of this paper was to examine and assess the performance of the coating and its influence on surface hardness, in- vitro corrosion, wear rate and friction coefficient. The results exhibited that the TiN coating led to an enhancement of the surface hardness of 23.1 GPa and modulus of elasticity of 224.6 GPa. In-vitro corrosion investigations showed better corrosion protection for the coated alloy in both simulated body fluid and artificial saliva compared to the uncoated alloy. The coefficient of friction (~ 0.4) of the coated alloy was almost 30% less than that of the TNZ alloy, and the wear rate of the coated TNZ was 0.62 ± 0.07×10⁻⁵ mm³/Nm compared to 3.9 ± 0.8×10⁻⁵ mm³/Nm for the uncoated sample. The obtained results indicate that coating the TNZ alloy with TiN may be a promising option for biomedical uses.