电流密度对镀铜石墨-铜复合材料载流摩擦磨损性能的影响

Current-Carrying Tribological Properties of Cu-Coated Graphite-Copper Composites with Different Current Densities

本文基于MZL-200H型高速载流摩擦磨损试验机,研究了电流强度变化对镀铜石墨-铜复合材料摩擦学性能的影响规律,通过磨损表面分析,揭示复合材料的损伤机制。研究表明:采用化学镀可以有效改善石墨与铜基体的界面接触能力,表现出石墨相没有出现团聚现象,而是均匀分布在相互连通的连续铜基体中;复合材料的摩擦因数和磨损率相比纯铜有明显的降低,其中摩擦因数随电流的增加而降低,磨损率随电流的增加而升高;随着电流的增大,磨损表面出现大量的电弧烧蚀坑,且坑内还附着一层密集细小的熔融重凝的铜颗粒,磨痕的宽度和深度有明显的提升;复合材料的损伤机制主要以熔融和电弧侵蚀为主,同时伴随磨粒磨损,黏着磨损和氧化磨损。

In this study, the effects of current densities on tribological properties of composites were studied using MZL-200H high speed current-carrying friction and wear testing machine. The damage mechanism of composites was revealed by the worn surfaces analysis. The results show that electroless plating could effectively improve the interfacial contact ability of graphite and copper matrix, and the graphite phases doesn’t agglomeration, and uniformly distribute in the connected continuous copper matrix. The friction coefficient and wear rate of composites are significantly lower than that of pure copper, in which the friction coefficient decreases with an increase in current density, and the wear rate increased. A large number of arc ablation pits appeared on the wear surface with an increase in current density. A dense layer of molten and re-coagulated copper particles is attached in the pits, and the width and depth of wear scars are significantly improved. The main damage mechanisms of the composites are melting and arc erosion, which are accompanied by abrasive wear, adhesive wear and oxidation wear.