Environment Friction And Wear Properties. Magnetron Sputtering Mos_x / Mos_x-mo Nano-multilayer Composite Films

Upon the application background of solid lubricants and wear resistant materials, the deposition process, microstructures and tribological properties of MoS_x/MoS_x-Mo self-lubricated composite multilayer films were investigated. In this paper, the effect of deposition pressure and different Mo contents on the microstructure, morphology, composition and tribological properties of MoS_x/MoS_x-Mo composite multilayer films was discussed, in order to meet the demand of applications in vacuum and in humid air.The MoS_x/MoS_x-Mo composite multilayer films with different Mo contents were deposited on steel substrates using pure MoS₂ target and MoS₂-Mo composite target, which produced from ball-milling 2H-MoS₂ and Mo powders. To determine the effect of argon pressure, the composite films were deposited at Ar pressures between 0.24-1.20 Pa, while other deposition parameters, such as substrate temperature, bias voltage and deposition power kept constant.The microstructures, morphology, and composition of the MoS_x/MoS_x-Mo composite multilayer films deposited by d.c magnetron sputtering were systematically investigated by means of XRD, SEM, AFM, EDS. The relationships between deposition pressure, Mo contents and microstructure, morphology of films were also discussed. Under low deposition pressure and low Mo content, the films have dense and featureless morphologies with pronounced basal plane orientation and well multilayer structures. With increasing the deposition pressure and Mo content, the films became columnar structure, and basal plane orientation reduced.On the basis of the microstructure of MoS_x/MoS_x-Mo composite multilayer films, the adhering force to the substrate and tribological properties of the composite films were investigated with scratch tester and ball-on-disk tribometer, respectively, and the morphology of the worn surfaces was characterized by scanning electron microscopy (SEM). The results showed that the adhesion of the composite films was decreased with the increase of the deposition pressure and Mo content. Through from changing the experimental parameters, it revealed that the friction coefficient decreased with increasing contact stress, while with the increasing of sliding velocity the friction coefficient and wear rate were first decreased and then increased. The film with Mo 5 at.% deposited at a deposition pressure of 0.24 Pa had the best tribological properties and environment stability.