Influence of glycerol dispersions of graphene oxide on the friction of rough steel surfaces.

The tribological properties of graphene have become an object of great scientific interest. However, the graphene oxide friction performance on rough surfaces remains comparatively unexplored. In this work, we focused on the effect of the multilayer graphene oxide (GO) dispersions in glycerol on the steel-steel tribosystem. Macroscale tribological tests were performed using a tribometer having a pin-on-disc configuration (normal loads 98 and 196 N, rotating speed 200 rpm). The wear samples were made of 40Cr steel with a roughness of about 110 nm. The study of the morphology of worn surfaces showed the dependence of lubricant efficiency on GO concentration. The use of 0.025 wt% GO led to the formation of a movable lubricating layer without deposition of tribofilm. The lowest friction coefficient was found at a concentration of 0.05 wt%. The decrease correlated with the formation of tribofilm on the steel surface. At high GO concentration (0.10 wt%), the agglomerated GO particles scratch the rubbing surfaces, and the friction coefficient increases significantly. • The influence of graphene oxide glycerol dispersions to lubrication of steel • AFM study of steel rubbing surface • Concentration dependence of lubricating properties of graphene oxide dispersions • Decreasing of friction coefficient in graphene oxide lubrication [ABSTRACT FROM AUTHOR]