Tribology properties of hybrid graphene oxide materials as lubricant additives

Graphene oxide was synthesized by the modified Hammers method. With managed hydrolysis in isopropanol solution obtained hybrid material “graphene oxide - copper oxide nanoparticles”. The phase composition of the hybrid material was studied by X-ray phase analysis and UV-visible spectroscopy. By ultrasonic processing dispersions of synthesized materials in glycerol were produced. The concentration of lubricating additives in the lube oil was 0.05 wt. %. The tribological properties of dispersions were investigated using a pin-on-disc friction machine. Tests showed that in the presence of graphene oxide, the friction coefficient was ~0.02, while with the addition of a hybrid material, the coefficient of friction was ~0.035. This is due to various mechanisms of lubrication. Reduction of the coefficient of friction in the presence of graphene oxide is associated with the formation of tribocarbon on the porosity of frictional contacts. While the addition of a hybrid material containing the CuO nanoparticles leads to the formation of a third body.