Ultralow concentration of graphene oxide nanosheets as oil-based lubricant additives

The nano-lubricant can largely enhance the tribological property of base oil, while the higher addition will cause a serious aggregation of nanoparticles. In this paper, the hexadecane-based oil (16C) with ultralow concentration of graphene oxide (GO) nanosheets as lubricant additives were successfully prepared by phase transfer method. The tribological behavior of the hexadecane with different concentration of GO has been investigated by subjecting it to macroscopic ball-on-disc friction tests using SRV-4 tribometer. The steady-state coefficients of friction (COF) of 16C with 10 mg/L GO were ca. 0.146. Based on the tribological tests and analysis of the wear scar, a lubrication mechanism was proposed. It is believed that the adsorption of GO nanosheets on the lubricated surfaces of both the ball and disk is the key to reduce friction and wear. The proper addition of GO nanosheets can easily enter into the contact area and efficiently protect the surface of the sample from wear.