Modified graphene as novel lubricating additive with high dispersion stability in oil

摘要

Graphene is a promising material as a lubricant additive for reducing friction and wear.Here,a dispersing method which combines chemical modification of graphene by octadecylamine and dicyclohexylcarbodiimide with a kind of effective dispersant has been successfully developed to achieve the remarkable dispersion stability of graphene in base oil.The stable dispersion time of modified graphene(0.5 wt%)with dispersant(1 wt%)in PAO-6 could be up to about 120 days,which was the longest time reported so far.At the same time,the lubricant exhibits a significant improvement of tribological performance for a steel ball to plate tribo-system with a normal load of 2 N.The coefficient of friction between sliding surfaces was~0.10 and the depth of wear track on plate was~21 nm,which decreased by about 44%and 90%when compared to pure PAO-6,respectively.Furthermore,the analysis of the lubricating mechanisms in regard to the sliding-induced formation of nanostructured tribo-film has been contacted by using Raman spectra and TEM.