Cooperative enhancement of tribological and electrical properties of copper composites by decorating graphene with GQDs

Abstract A novel approach of decorating graphene surface with graphene quantum dots (abbreviated as GQDs@Gr) was presented to achieve superior tribological properties in Gr/Cu composites. The prepared GQDs@Gr hybrid reinforcement possessed superior dispersion and had achieved strong interface bonding with Cu matrix. GQDs@Gr/Cu composite showed a good combination of wear resistance and electrical conductivity due to the synergistic effect of GQDs and Gr. Specifically, the coefficient of friction (COF) was reduced to 0.3, the wear rate (WR) was 2.13 × 10 –5 mm 3 ·N −1 ·m −1 (only a quarter of pure copper), and maintained the electrical conductivity of 96.5%IACS (international annealed copper standard). As a result, delamination, fracture, and plow furrows on the wear surface of Gr/Cu composite indicate that fatigue and abrasive adhesive wear are the main wear mechanisms. Wear surface lubrication film and strong interface bonding ensure better comprehensive performance of GQDs@Gr/Cu composite.