Friction and Wear Behavior of Self-lubricating La-Ti/WS2 Films by Unbalanced Magnetron Sputtering

Abstract:

The solid lubrication films with high hardness and low friction coefficient should be developed to satisfy the severe working conditions of mechanical rotating parts of spacecraft. The pure WS₂ film, Ti doped WS₂ composite film (Ti/WS₂) and La-Ti doped WS₂ composite film (La-Ti/WS₂) were prepared by unbalanced magnetron sputtering. The micro morphology, composition, hardness and tribological performance of the films were examined. Results show that compared with pure WS₂ films and Ti/WS₂ composite films, the microstructure of La-Ti/WS₂ composite film becomes more compact. Meanwhile, the hardness and elastic modulus of La-Ti/WS₂ composite film also increase significantly. Furthermore, the friction coefficient of La-Ti/WS₂ composite film decreases, and the hardness/elastic modulus (H/E) ratio of La-Ti/WS₂ composite film increases, which suggests that the wear rate of La-Ti/WS₂ composite film is reduced. It is indicated that La doping contributes to the formation of stable transfer film on the friction contact surface, and thus improves the wear resistance and carrying capacity of La-Ti/WS₂ composite film.