Tribological properties of Ti6Al4V alloy co-Implanted with N and F ions

The surfaces of Ti6Al4V alloy were co-doped with N and F by plasma immersion ion implantation. The influence of the reaction conditions, including the bias voltage, contents of N and F, and implantation time, on the microstructures, phase-structures and tribological properties of the alloy was investigated X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy and conventional mechanical probes. The results show that co-implantation of N and F ions significantly improved the mechanical behavior of Ti6Al4V alloy. To be specific, the surface nano-hardness and elastic modulus increased, accompanied by decreases of the friction coefficient and wear rate, possibly because of a decrease of surface roughness and formation of TiO₂, TiF₃, TiF₄ and TiN phases in the modified layers. Abrasive wear had a major impact. F-ion-implanted at-20 kV, the Ti6Al4V alloy displayed the best tribologicalbehavior of the samples.