Tribological properties of GO/modified SiO2 combination as lubricant additive for bearings

This study investigates the tribological performance of GO/modified SiO2 (GMS) as a composite additive and elucidates their synergistic mechanism. A four-ball friction testing machine and a Timken friction testing machine were used to evaluate the tribological performance of the GMS lubricating oil. The results show that the addition of 0.03 wt% GO and 0.12 wt% modified SiO2 (Mod-SiO2) in the oil resulted in a 48.70% reduction in average friction coefficient, a 60.56% decrease in wear, and a 1.43% increase in PB, compared to pure GO oil. Compared to pure Mod-SiO2 oil, the average friction coefficient decreased by 46.09%, wear decreased by 51.40%, and PB increased by 1.38%. Furthermore, under different loads, the GMS lubricating oil exhibited outstanding capability in reducing frictional noise between the bearing rollers and outer ring, as well as mitigating the trend of temperature variation. The worn surfaces of the test rollers were analyzed using EDS, SEM, CLSM, TEM and Raman spectrum. The spherical Mod-SiO2 particles adhere to the flake-like GO, preventing agglomeration and facilitating better dispersion in the lubricating oil. Therefore, GMS exhibits its significant advantages and potential as a lubricant additive.