Microstructure, chemical and tribological investigations of MoxW1−xSy co-sputtered composite films

MoxW1−xSy composite films were co-sputtered by the combination of MoS2 and WS2 targets, which were shown to have much superior tribological performance with lower and more stable friction coefficient, longer durability and higher bearing resistance than pure MoS2 films in room temperature air with a relative humidity of 45–50%. Especially for the Mo0.6W0.4S1.6 (40 at.% WS2) composite film, an increase in durability of more than a one order of magnitude was reached. X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy were used to investigate the relationship between the microstructure and the tribological performance of the films. The composite films are shown to have a densified structure and accordingly improved oxidation resistance and lubrication properties. Moreover, the composite films have a lattice expansion in the c direction, along with a reduced the friction within the films.