NbMoWTa/Ag自润滑纳米多层膜的力学性能及摩擦学行为

In order to improve the wear resistance of high-entropy alloy film NbMoWTa and reduce its friction coefficient, NbMoWTa/Ag multilayer films with different modulation periods were deposited by magnetron sputtering on Si substrates. The characterization of nanomultilayers were systematically investigated by XRD, SEM and TEM. Its hardness and tribological properties were analyzed. The results showed that the multilayer films with different modulation periods have a high degree of crystalline. The hardness (5.62-8.39 GPa) of multilayers increases with the decrease of the individual layer thickness (100-5 nm). The plastic deformation mechanism changes from dislocations piling up against an interface mechanism to dislocation interface crossing mechanism when the thickness of monolayer decreases to 20 nm. When the thickness of monolayer is less than 10 nm, the hardness of the multilayer film is close to the high-entropy alloy film NbMoWTa (10.93 GPa). This may be caused by the transition from semi-coherent interface to coherent interface between NbMoWTa and Ag films with the decrease of individual layer thickness. Meanwhile, the experimental friction coefficient and wear rate of NbMoWTa film are 0.49 and 1.75×10^-5 mm³N^-1m^-1. The experimental friction coefficient and wear rate of the multilayer film with a layer thickness of 5 nm are 0.23 and 2.19×10^-5 mm³N^-1m^-1. The nanomultilayers prepared by adding 50% Ag in NbMoWTa ensures its high hardness and high strength, and realizes the coordinated control of wear resistance and self-lubrication through the multilayer design.