Effect of Sputtering Power on High Temperature Tribological Behavior of La-Ti/WS2 Composite Films

Under high temperature conditions, the crystal WS2 is easily oxidized to WO3, which has a great impact on the tribological properties of WS2 solid lubrication films. In order to improve the tribological properties of WS2 solid lubricating films at high temperatures, the co-doped La-Ti/WS2 composite films were prepared by unbalanced magnetron sputtering. The effects of target power on the structure and tribological properties of La-Ti/WS2 composite films were studied. The micromorphology, composition, mechanical properties and microstructure of the films were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), nano indentation and X-ray photoelectron spectroscopy (XPS). The high temperature tribological properties of composite films were researched by high temperature friction tester. The results show that La-Ti/WS2 composite films show excellent tribological properties when the target power is 20 W at high temperature. At this time, the H/E value of the composite film is the largest, the friction coefficient is the smallest with the average value of 0.012, and the wear rate is the lowest, which is 1.56x10(-8) mm(3)/N.m. This is mainly due to the production of rare earth oxides at the friction interface at high temperatures, which change the friction and wear mechanism of La-Ti/WS2 composite film, so that WS2 still has excellent tribological properties when it is damaged at high temperature, further expanding the scope of engineering application of WS2 composite films.