Temperature-Dependent Tribological Improvements in Low-Energy Nitrogen Ion Implanted Vanadium-Titanium Alloys

A detailed tribological characterization of low-energy, nitrogen implanted V5 at. %Ti alloy is presented. Samples were nitrogen-implanted at an accelerating voltage of 1.2 kV and 1 mA/cm2, up to a dose of 1E19 ions/cm2. The tribological properties of the alloys: microhardness, friction coefficient and wear resistance, have improved after ion implantation and this improvement increases as the implantation temperature increases. The microstructure of the alloys were analysed by transmission electron microscopy. A direct correlation between structural modifications of the nitrogen implanted layer and the improvement in their tribological properties is obtained. For samples implanted at 848 K a nanocomposite layer where the reinforcement particles are TiN precipitates forms. TiN precipitation appears as the responsible of the improvement in the tribological properties.