Unraveling the mechanical and tribological properties of a novel Ti5Si3/TiC nanocomposite coating synthesized by a double glow discharge plasma technique

A novel Ti5Si3/TiC nanocomposite coating has been successfully prepared on a Ti–6Al–4V substrate by a double cathode glow discharge technique to address its poor tribological properties. The microstructural features of the Ti5Si3/TiC nanocomposite coating were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The nanocomposite coating consisted of cauliflower-like Ti5Si3 grains with an average grain size of ~15 nm and TiC nanoparticles having an average grain size of ~15 nm distributed at its boundaries. The mechanical and tribological properties of the Ti5Si3/TiC nanocomposite coating were compared with those of a monolithic Ti5Si3 nanocrystalline coating. The results clearly showed that the Ti5Si3/TiC nanocomposite coating exhibited a unique combination of higher fracture toughness and hardness as compared to the monolithic Ti5Si3 nanocrystalline coating, which thus exerted a positive effect on its wear resistance.