Tribological properties of oleic acid-modified graphene as lubricant oil additives

Liquid phase exfoliated graphene sheets were modified by oleic acid and dispersed in lubricant oils as additives. The tribological behaviours of graphene-contained oils were investigated using a four-ball tribometer. The lubricant with optimized graphene concentrations of 0.02-0.06 wt% showed enhanced friction and anti-wear performance, with friction coefficient and wear scar diameter reduced by 17% and 14%, respectively.