Effect of target power on the structure and tribological Properties of La-Ti/WS2 composite films prepared by unbalanced magnetron sputtering

Abstract

The properties of Physical Vacuum Deposit (PVD) films could be improved by doping rare earth elements and other metal elements. In this paper, La-Ti/WS2 composite films were prepared by unbalanced magnetron sputtering. The effect of target power on the structure and properties of La-Ti/WS2 composite films was studied. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) were used to analyze the micro morphology, composition and crystal structure of the film. The hardness and friction and wear properties of the film were tested by nano-indentation and friction and wear testing machine. The results show that the structure and composition of La-Ti/WS2 composite films prepared by magnetron sputtering are affected by the target power. With the increase of the target power, the diffraction peak of WS2 (002) was shifted to the low θ value, the crystal surface spacing was decreased, the crystal lattice shrinked, the porous structure of La-Ti/WS2 composite films was decreased significantly, the coarse columnar crystal was refined significantly, and the film density was improved effectively. When the target power is 20 W, the sliding surface of La-Ti/WS2 composite film (002) is parallel to the surface, showing lower friction coefficient and better wear resistance; when the target power is 50 W, La-Ti/WS2 composite film has higher hardness, higher wear rate and poor wear resistance. The density and friction and wear properties of La-Ti/WS2 composite films can be improved by suitable La-Ti content.