Tribological Behavior of Copper-Graphite Composites Reinforced with Cu-Coated or Uncoated SiO2 Particles

Copper-graphite composites reinforced with SiO2 particles were fabricated by powder metallurgy technique. Electroless copper plating was introduced to improve the interfacial bonding between SiO2 particles and copper matrix. The microstructure, density, and hardness of the composites were characterized. The tribological properties, such as friction coefficient and wear rate of the composites, were studied using a pin-on-ring tribometer. The results show that the hard SiO2 can restrict the severe plastic deformation and adhesion contact in the process of wear. At the same time, parts of SiO2 particles can be broken into fine particles during wear process, which is helpful for decreasing adhesion wear and abrasive wear. Therefore, the addition of SiO2 leads to increasing friction stability and friction coefficient, and decreasing wear rate. In addition, the electroless copper plating improves the interfacial bonding between SiO2 and copper matrix, which prevents separation of SiO2 from copper matrix and further increase tribological properties of the composites.