The Effect of Ti Transition Layer on Lubrication-Conduction Properties of NbSe₂ Films

Ti-NbSe₂ films were deposited by radio frequency magnetron sputtering. The composition and structures were characterized by X-ray photoelectron spectrum (XPS), X-ray energy dispersive spectrum (EDS), X-ray diffraction (XRD) and field-emission scanning electron Microscope (FE-SEM). The mechanical and tribological properties were measured by nano-Triboindenter and tribometer in ball-on-disk. The static contact resistance was investigated by four-probe-meter. The results showed that the Ti transition layer could regulate the Se/Nb atomic ratio and crystallinity into the films. The adhesion strength of the film-substrate and the mechanical properties of films were improved distinctly with the increased thickness of Ti transition layer, and the films showed the remarkable NbSe₂ (002) plane which are beneficial for lubrication-conduction capabilities of NbSe₂ films. However, when the thicknesses of Ti layer exceeded the optimum 30 nm, Se/Nb atomic ratio and the crystallinity in the films reduced, whereas the amorphous metal increased in this stage. Furthermore, while the electrical conductivity property enhanced, the tribological property of the films deteriorated dramatically. As a result, a suitable thickness (30 nm) of Ti transition layer can properly promote the lubrication-conduction properties of NbSe₂ films.