A Critical Review of Copper-Graphene Nanocomposites: From Processing To Tribological Applications

Abstract Copper-graphene nanocomposites have emerged as promising materials in tribology owing to their unique combination of high mechanical strength, excellent thermal conductivity (K), and self-lubricating behavior. Incorporation of graphene derivatives such as graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs) has been shown to reduce the coefficient of friction (COF) by up to 60% and wear rates by 50–70%, primarily through the formation of stable graphene-based tribofilms. Advanced processing techniques, including spark plasma sintering (SPS), molecular-level mixing, and electrodeposition (ED), enable uniform graphene dispersion and strong interfacial bonding, yielding composites with 20–50% lower friction and 30–70% lower wear rates at reinforcement levels as low as 0.1–0.5 vol%. Furthermore, hybrid strategies, such as combining CNTs with silicon carbide, enhance wear resistance by up to 60% under high-load conditions. Mechanical enhancements have also been reported, with yield strength improvements exceeding 200% and hardness increases of 50–100% in optimized systems. However, excessive reinforcement (> 2.0 vol%) can lead to agglomeration, porosity, and performance degradation. This review critically analyzes the processing-structure-tribology relationships of Cu-Gr nanocomposites, emphasizing the balance between reinforcement level, dispersion quality, and interfacial engineering. The findings underscore their potential as next-generation self-lubricating materials for bearings, electrical contacts, and high-performance sliding systems.