Tribo-Induced Interfacial Lubrication Performance and Self-Repair Mechanism of Oleylamine-Grafted Chlorinated Graphene

Understanding the mechanism of action of graphene oxide (GO)-based lubrication materials is of great significance to effectively suppress the surface damage accumulation of bearing steel during service. However, GO typically exhibits weak interfacial adsorption and poor dispersion stability, severely limiting its ability to form a dynamic tribofilm during friction. In this study, we synthesized an efficient lubricant, oleylamine-grafted chlorinated graphene (OA/Cl-GO), using GO as the carrier and introducing lipophilic terminal groups through chlorination and interfacial covalent modification. The lubrication performance of GO and OA/Cl-GO in steel/steel friction pairs was evaluated under sliding wear conditions, and the effects of the additive concentration, chemical composition, and microstructure on the OA/Cl-GO interfacial lubrication behavior were systematically investigated. The results showed that the lubricating performance of OA/Cl-GO was significantly better than that of the GO at an optimal concentration of 0.15 wt %, which could reduce the coefficient of friction and wear scar diameter of the base oil by 30.1 and 22.7%, respectively. During the sliding wear process, the synergistic effects of charge adsorption, protective adsorption films, and tribochemical reaction films effectively induced the formation of a "sliding-rolling" cooperative load-bearing behavior of OA/Cl-GO nanosheets at the interface. As a result, a dynamic repair mechanism was developed on the friction surface, which effectively suppressed the damage progression of the bearing steel. This study provides a theoretical foundation and technical guidance for developing nanolubricants with high compatibility with bearing steel interfaces.