Microstructure, mechanical and tribological properties of TaWN composite films

A series of TaWN films with different W contents were prepared using reaction magnetron sputtering, and the microstructure, mechanical and tribological properties were investigated by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), scanning electron microcopy (SEM), energy dispersive spectrometer (EDS), nano-indentation and tribometer. The result showed that the TaWN films were composed of fcc-(Ta,W)N phase and hcp-(Ta,W)N phase. The microhardness of the TaWN films increased initially and then decreased with the increase of W content, the maximum value was 32.2 ± 0.5 GPa at 16.2 at% W. The microhardness enhancement was attribute to solid solution strengthening and the change of phase structure. The average friction coefficient and wear rate of TaWN films decreased gradually from 0.72 to 1.26 × 10−7 mm2/N at 0 at% W to 0.44 and 3.95 × 10−8 mm2/N at 22.8 at% W, respectively.