The Preparation And Tribological Properties Of Mo-S-N Composite Films

MoS2 thin films have very low friction coefficient in vacuum and are widely used in solidlubrication treatment of various active components of spacecraft,However,with the rapiddevelopment of space science and technology,the launch activities of spacecraft are graduallytransferred to the low latitude coastal areas,based on the need of improving the launchefficiency,safeting and transporting convenienc,This trend will increase the time for thespacecraft to be exposed to moist air during the launch waiting period,causing the life of theMoS2 film to shrink obviously.Short,the lubrication performance drops sharply.The doping ofnon-metal nitrogen can overcome the problem that MoS2 films are prone to wet oxidation andmetal doping is insufficient in vacuum.Mo-S-N composite thin films with different nitrogen content were prepared bynon-equilibrium magnetron sputtering with four target closed field.The microstructure andmorphology of the composite films were analyzed by XRD,AFM?TEM and SEM,and thehardness of the films was measured by nano pressure entry.The friction and wear test machinewas used to detect the friction of the film.Learning performance.The effects of differentnitrogen flow rates on the microstructure,mechanical properties and Tribotogical Properties ofthe composite films were studied.The results show that the as-prepared Mo-S-N composite film has an amorphous structureas a whole,and the surface of the film is a typical island-like aggregation state.In addition,the flow of nitrogen gas increases,the size of the islands on the surface of the film decreases,andthe structure becomes denser;Under the condition of low nitrogen flow rate,a large number ofdendritic MoS2 nanocrystals are embedded in the amorphous structure in the composite film,amorphously wrapped nanocry stalline structure,and with the increase of nitrogen flow rate,thedendritic MoS2(002)nanocrystals and MoS2(101)decreased,and a few nanocrystals ofMo2N(103)facets appeared in the composite film,the flow rate of nitrogen continued toincrease,and the composite film gradually transformed to an amorphous structure.Furthermore,The incorporation of nitrogen effectively reduces the surface roughness of the MoS2 thin film,and the roughness of composite films decreased with the increase of nitrogen flow rate.The addition of nitrogen can improve the hardness and modulus of elasticity of the composite film.When the nitrogen flow rate is 2sccm,the hardness and modulus of the composite film reach the maximum value of 10.4GPa and 117.0GPa,respectively.In addition,compared with pure MoS2 films,Mo-S-N composite films have better friction and wear resistance at low nitrogen flow rate.When the nitrogen flow rate is 2sccm,the Mo-S-N composite film has more stable friction coefficient and smaller specific wear rate under different loads,and the friction coefficient gradually decreases with the increase of load,and the composite film has no cracks and defoliation in the appearance of the wear mark after friction 3500s,and the boundary is clear.Compared with normal temperature,the friction property of composite film is better at 350 ? high temperature.