Self-lubricating TiSi(V)N thin films deposited by deep oscillation magnetron sputtering (DOMS)

Abstract

In last years, vanadium containing coatings have been introduced as possible candidates for self-lubrication due to their good tribological properties. The main objective of the present work was to investigate the effect of V addition on the morphology, structure, and tribological performance at room temperature of Ti-Si-N films deposited by high power impulse magnetron sputtering (HiPIMS) in deep oscillation magnetron sputtering mode (DOMS) with two different peak powers. All coatings showed a fcc NaCl-type structure. A shift of the diffraction peaks to higher diffraction angles was observed with increasing V content, suggesting the formation of a substitutional solid solution of V in the TiN phase. However, depending on the peak power, different preferred orientations and morphologies were achieved. Independently of the V content in the coatings, low peak power promoted a [111] preferred orientation and a columnar morphology, while high peak power favored the [200] preferred orientation and a compact morphology. V additions had a beneficial effect on the tribological behavior of the coatings by decreasing the wear rate and the friction coefficient of the TiSiN films. Abrasive wear was found to be the main wear active mechanism taking place on the reference Ti-Si-N films, while polishing wear took place in V rich coatings. The improved tribological properties of the V-containing coatings were attributed to the formation of the lubricious V2O5 on the wear track.