石墨表面金属化对铜基复合材料摩擦学性能的影响

Influence of surface metallization of graphite on tribological properties of Cu-matrix/graphite composite materials

利用化学镀技术制备镀铜和镀镍石墨粉,采用粉末冶金复压复烧工艺制备铜基石墨自润滑复合材料,测试了复合材料的摩擦磨损性能,利用X射线衍射、扫描电镜和能谱仪等分析该复合材料的结构、摩擦磨损性能及机理。结果表明:石墨表面铜、镍镀层改善了石墨和铜合金基体界面结合,摩擦过程中所形成的润滑膜与基体粘附性好,显示出更好的润滑减摩效果,摩擦副摩擦因数由0.24降低到0.20,磨损率降低约50%;实验条件下,6%(质量分数)石墨铜基复合材料经历轻微磨损、中等磨损和严重磨损3个磨损过程;而6%镀铜、镀镍石墨铜基复合材料只经历轻微磨损和中等磨损两个磨损过程。

The graphites coated with copper or nickel were prepared using electroless plating technology. And the Cu-matrix/graphite composite materials were made by repressing and resintering process of powder metallurgy. The tribological properties of the composites were investigated on a tribometer. The composite structure, wear process and wear mechanism were analyzed by XRD, SEM and EDS. The results show that the interfacial combination between the graphites and copper-matrix is greatly improved by the graphite particles coated with copper or nickel, resulting in the good adhesion of the lubricating film to matrix. The composites with coated graphite particles exhibit better anti-friction and anti-wear, i.e., the coefficient of friction decreases from 0.24 （graphite without coatings） to 0.20 （with coatings）, and the wear rate is decreased by 50%. Under this test conditions, the wear process of Copper matrix composites with 6%（mass fraction） graphite have three typical stages, such as, slight wear stage, medium wear stage and severe wear stage The wear process of the composites containing 6% graphite coated with copper or nickel has only two typical stages, namely slight wear stage and medium wear stage.