A Hybrid Graphene-Reinforced Copper Matrix/Multilayer Composite Coating System for High-Load Solid Lubrication

Abstract

Copper plating of industrial components is common. However, the application of copper to moving parts is limited due to its poor tribological properties. In this study, a novel nickel-flashed, graphene nanoplatelet-reinforced copper matrix coating (referred to as ML(Ni)) on AISI 52100 steel exhibited stable and long-lasting friction coefficients (μ < 0.2) that were substantially lower than from similarly-prepared coatings that omitted nickel and graphitic material. Chemical, structural and mechanical analysis of the wear tracks on ML(Ni) after pin-on-disk testing identified key contributions that promote lubrication synergy. Moreso, the roles of individual components (Ni, Cu and GnP) within ML(Ni) were probed in detail to demonstrate that its hybrid composite structure is a promising candidate for use in high-load engineering applications.