Effect of few layer graphene additive on the tribological properties of lithium grease

Abstract The tribological properties of lithium grease with few layer graphene (FLG) additive were studied. Three‐dimensional surface topography, FESEM with EDS and XPS were used to analyse the morphology, distribution of elements and chemical states on the wear spots. The results show that 0.1 wt% FLG content produced maximum reduction rate of the friction coefficient and minimum wear spot diameter (WSD). And the best results obtained under larger load and lower speed. Fe3O4 was found to be the main component of the chemical reaction film formed on the friction surface when pure lithium grease lubrication was applied. However, when FLG‐containing lubricating grease was used instead, the boundary film was mainly composed of Fe2O3 and adsorbed FLG. The effectiveness of FLG in reducing the friction coefficient and WSD of lithium grease is mainly attributed to its large specific surface area, great number of active groups and typical layered structure.