Sliding wear behavior of copper-based composites reinforced with graphene nanosheets and graphite

The mechanical and tribological properties of hot-pressed copper-based composites containing different amounts of graphene nanosheets (GNSs) are compared with those of copper-graphite (Gr) composites fabricated by the same method. The results show that the Cu-GNSs composites exhibit higher relative density, microhardness and bending strength compared with Cu-Gr composites with the same volume fraction of GNSs and Gr. Moreover, the friction coefficients and wear rates reduce significantly by the addition of GNSs, whereas the limited impact on reducing friction and wear is found on graphite. The abrasive and delamination wear are the dominant wear mechanisms of the composites. It is believed that the superior mechanical and tribological performances of Cu-GNSs composites are attributed to the unique strengthening effect as well as the higher lubricating efficiency of graphene nanosheets compared with those of graphite, which demonstrates that GNS is an ideal filler for copper matrix composites, acting as not only an impactful lubricant but also a favorable reinforcement.