Microstructure and tribological behaviors of magnetron sputtered WS2/Fe/a-C/Fe multilayer films with various deposition temperatures

WS2/Fe/a-C/Fe multilayer films were prepared by using magnetron sputtering technique under various deposition temperatures. The composition, microstructure, mechanical and tribological properties of the films were characterized by energy dispersive spectroscopy (EDS), X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), nano-indenter, scratch tester, film stress tester and ball-on-disk tribometer. With increasing deposition temperature, the film exhibits a morphology change from block-like to featureless, accompanied by a microstructural densification effect, its S/W ratio decreases from 1.14 to 1.04, and the hardness and adhesion are gradually enhanced. The films with deposition temperature >= 150 degrees C present better tribological performance than WS2/a-C multilayer film in vacuum and humid air. The film deposited at 300 degrees C achieves the highest hardness (9.0 GPa), a good adhesion (25.6 N), and the best tribological performance with a steady-state friction coefficient of 0.212 and wear rate of 7.07 x 10(-15) m(3) N-1 m -1 in humid air, and steady-state friction coefficient of 0.165 and wear rate of 3.09 x 10(-15) m(3) N-1 m(-1) in vacuum.