Tribological Properties of Muscovite/La2O3 Composite Powders as Lubricant Additives

摘要

Muscovite/La2O3 composite powders were prepared by ball-milling solid-state chemical reaction at room temperature. The phase composition and micromorphology of the composite powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). The tribological properties of different samples were tested and compared using four-ball wear testing on an MMW-1A multifunctional friction and wear testing machine. The SEM micrography and energy spectrum of the composite powders illustrated that La2O3 particles were coated on the surface of muscovite particles. The results of the friction tests indicated that lubrication oil with muscovite/La2O3 composite powders presents better friction reducing and antiwear properties than that of the base oil, and the friction coefficients and diameters of wear scars decreased by 47.6 and 11.2% using 500SN base oil with 0.6g/L of muscovite/La2O3 composite powders as additives, respectively. The composite powders with 5 wt% La2O3 present the best comprehensive tribological properties. The micromorphology and chemical composition of the worn surface were analyzed by SEM and EDX, which confirm that the composite powders directly participate in the complicated physicochemical process of reactions on the worn surfaces, therefore improving the tribological properties of the base oil.