Tribological properties of self-lubricating TiSiVN coatings at room temperature

Abstract

In the last years, vanadium rich coatings have been introduced as possible candidates for self-lubrication due to their optimum tribological properties. In the present investigation, the influence of V incorporation on the wear performance of TiSiN films deposited onto WC substrates by d.c. reactive magnetron sputtering is reported. The results achieved for TiSiVN films were compared and discussed in relation to Ti0.80Si0.15N, TiN and Ti0.82V0.15N coatings prepared as references. The tribological properties of the coatings were evaluated at room temperature on a pin on disk tribometer equipment using two different counterparts: Al2O3 and HSS balls. The wear tracks, ball-wear scars and wear debris were characterized by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDS). Tribological tests indicated that the wear rate and the friction coefficient of Ti0.80Si0.15N coating decreased with continuous increase of V content being the overall behavior strongly dependent on the counterpart ball material. For Al2O3 balls the wear rate and friction coefficient of coatings were much lower compared to sliding against HSS steel balls. Ti0.80Si0.15N showed the lowest wear resistance among all tested coatings, independently of the counter-body. For V rich coatings tested with Al2O3 balls the polishing wear mechanism was observed, whereas adhesion wear took place when tested against HSS balls.