Preparation And Friction Properties Of MoS₂/WS₂ Composite Films Deposited By Magnetron Sputtering

With the rapid development of aerospace science and technology,the demand of the material's lubrication and wear-resistance become higher and higher.In out space,because of high vacuum and low temperature environment,the use of liquid lubricants was restricted.As the traditional solid lubricants,graphite and diamond-like carbon material have good friction properties in the air,but friction properties became bad rapidly in the vacuum.In order to develop the demand of high-reliability space technology,the study of solid lubricating film which have a good stable environment and excellent wear resistance properties are needed.MoS₂ films and WS₂ films as solid lubricant film have widely used in vacuum,but the properties of films will debase in air especially in humid air.It was found that nanocomposite films show low friction and long endurance in comparison to single-layer film.in order to improve the friction properties of single-layer film,in this study,MoS₂ /WS₂ composite films have been successfully prepared by magnetron sputtered method from a pure MoS₂ target and a pure WS₂ target and from a MoS₂/WS₂ composite target.The influence of different process parameters on composite films was studied,the friction properties of composite films also be compared with pure films.The major research are followed:MoS₂/WS₂ composite films were deposited onto stainless steels and silicon substrates using ECR DC magnetron sputtering from a pure MoS₂ target and a pure WS₂ target.The morphology and microstructure of the MoS₂/WS₂ composite films were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM) and energy dispersive X-ray spectroscope(EDS).The mechanical properties were measured by HH-3000 binding strength Scratch tester and nano-indentation test system.Friction properties of the MoS₂/WS₂ composite films were characterized using Friction testing machine(UMT-2).The results show that the MoS₂/WS₂ composite film is nano-composite film,the surface of the composite film is composed of 50 nm～100nm particles,the particles of MoS₂/WS₂ composite film Less than that of pure films,the friction properties of MoS₂/WS₂ composite film better than that of pure films.The tribological properties of the MoS₂/WS₂ composite films were investigated using the ball-on-disk tribometer under the different tribological conditions.The friction coefficient of films decreased and there was little change in friction stability. Compare the friction properties of MoS₂/WS₂ composite films with that of the pure MoS₂ films in ambient air,it was found that the friction properties of MoS₂/WS₂ composite films are better than pure MoS₂ films in ambient air.MoS₂/WS₂ composite films were also deposited using ECR DC magnetron sputtering from a MoS₂/WS₂ composite target.Through the morphology analysis and friction properties test,the result shows that the best technical parameters of Sputtering MoS₂/WS₂ composite film are:sputtering pressure is 4.0 Pa,sputtering power is 150 W.The surface topography of MoS₂/WS₂ composited film are similar to pure MoS₂ film,but the particles are smaller than pure MoS₂ film,the structure of MoS₂/WS₂ composite film are more dense.In the atmosphere,the friction properties of MoS₂/WS₂ composited film are better than pure MoS₂ film,the friction properties in dry air are better than in humid air.