On the tribological behaviors of Cu matrix composites with different Cu-coated graphite content

Graphite/Cu composite is widely used in pantograph slide plates. To further understand its lubrication behaviors, the tribological properties of graphite/Cu composites with different graphite content were studied using ball-on-disk wear tests. The results reveal that the composites contain only graphite and Cu phases. The tribological results show that the friction coefficient and wear rate of 7 wt.% graphite/Cu composite were decreased 7.7% and 12.7%, respectively, compared with 5 wt.% graphite/Cu. However, both friction coefficient and wear rate increased with the graphite content exceeding 7 wt.%. The excellent tribological properties of the composites were mainly attributed to the synergistic action of the oxidative trib o-layer and graphite lubricant film, which is composed of graphite, Cu, CuO, and Fe2O3. The wear mechanism of the graphite/Cu composites was mainly abrasive wear, accompanied by adhesion and oxidation wear.