Preparation and Tribological Properties of Cu-doped Muscovite Composite Particles as Lubricant Additive

Cu-doped muscovite(Mu) composite particles, abbreviated as Mu/Cu, were prepared via liquid phase reduction method. The morphologies, phase composition and elementary distribution of the as-prepared Mu/Cu and raw muscovite particles were characterized by means of scanning electron microscope(SEM), X-ray diffraction(XRD) and energy dispersive spectrometry(EDS). The tirbological properties of Mu/Cu and Mu as lubricant additives in lithium grease were evaluated on a block-ring tribomachine. The roughness, 2D and 3D morphologies and elementary distribution of block worn surface were analyzed to explore the tribogical mechanism. The results show that muscovite are evenly coated by the cubic Cu nanoparticles in composite particles. Both Mu/Cu and Mu can effectively improve the tirbological properties of lithium grease and Mu/Cu exhibits better tribological performance than Mu. The friction coefficient of Mu/Cu is decreased by 69.2% as compared to that of lithium grease. The layer structure of muscovite is synergistic with Cu nanoparticles in contribution to the formation of lubricant film mainly consisting of O, Si, Fe, Cu as well as Al elements on the block worn surface thereby further reducing the friction and wear.