Synergistic effects of fabrication techniques and the interface structure on the tribological properties of reduced graphene oxide/CuCr composites

Abstract

While the copper/graphite composite offers commendable anti-friction and wear resistance, it falls short in fulfilling the demands of specific applications such as special brushes, high-speed rail overhead conductors, and sliding contact materials. Due to its exceptional mechanical, electrical, frictional, and wear-resistant properties, reduced graphene oxide (RGO) is considered a promising reinforcement material for copper-based wear-resistant materials. In this study, we synthesized RGO/CuCr composites using flake powder metallurgy and spark plasma sintering (SPS) techniques. The formation and evolution of lubricative films on the RGO/CuCr composite's worn surface were scrutinized, alongside the effects of reinforcement concentration and frictional load on friction-wear characteristics. Notably, increasing the RGO content from 0 to 4.0 vol% led to a reduction in the average friction coefficient from 0.81 to a minimum of 0.314, concurrent with a 62.4% drop in the wear rate. The overall enhancement in properties can largely be credited to the optimized interfacial adhesion between RGO and the CuCr matrix facilitated by in-situ interfacial carbides and the inherent self-lubrication capability of RGO. A developed physical model showcased a direct relationship between the friction coefficient of RGO/CuCr composites and the experimental load, offering a quantitative interpretation of the load's influence on the composite's friction coefficient. Therefore, this research paves a theoretical and practical pathway to engineer high-performing RGO-reinforced copper matrix composites for wear-resistant applications.