镀铜石墨/铜复合材料的组织和摩擦磨损性能

Microstructure,Friction and Wear Properties of Copper-CoatedGraphite/Copper Composites

本实验以电解铜粉为基体,镀铜石墨为润滑相,采用放电等离子烧结技术(SPS)制备镀铜石墨/铜复合材料,研究了镀铜石墨含量对复合材料微观组织、硬度、孔隙率和摩擦磨损性能的影响。结果表明:镀铜石墨均匀分散在Cu基体中能细化晶粒、均匀组织,石墨表面镀铜层能够增强石墨与Cu基体的界面结合。当镀铜石墨含量超过4wt%,复合材料的硬度和孔隙率变化幅度明显增大。镀铜石墨具有细晶强化作用,能提升复合材料的硬度,其含量为4wt%时,复合材料的硬度达到最大值57.8HV,但镀铜石墨含量和孔隙率的共同作用使得复合材料的硬度呈先增大后减小的趋势。随着镀铜石墨含量增加,复合材料孔隙率逐渐增大,摩擦系数、磨损量逐渐减少,镀铜石墨含量为8wt%时,复合材料的摩擦系数、磨损量相比纯铜分别降低63.9%、96.3%。镀铜石墨作为润滑相紧密镶嵌在铜基体中,显著提高了复合材料的摩擦磨损性能。复合材料摩擦磨损机理主要为磨粒磨损、粘着磨损和氧化磨损。

Copper-coated graphite/copper composites were prepared by spark plasma sintering(SPS)with electrolytic copper powder as matrix and copper-coated graphite as lubrication phase.The effect of graphite content on microstructure,hardness,porosity,friction and wear properties of the composites were investigated.Results shows that the copper-coated graphite can be uniformly dispersed in the Cu matrix to refine the grains and uniform structure.The copper-coated layer on the graphite surface can enhance the interfacial bonding strength between graphite and Cu matrix.When the content of copper-coated graphite was over 4wt%,the change range of hardness and porosity of the composite material increased significantly.The copper-coated graphite had a fine-grained strengthening effect to enhance the hardness of the composite.When the content of copper-coated graphite was 4wt%,the hardness reached a maximum of 53.6HV,but the combined effect of the copper-coated graphite content and the porosity causes the hardness to increase first and then decrease.As the content of copper-coated graphite increases,the porosity of composites increased remarkably,and the friction coefficient and wear amount decreased gradually.When the content of copper-coated gra-phite was 8wt%,the friction coefficient and wear of composites were reduced by 63.9%,96.3%,respectively,compared with pure copper.The copper-coated graphite was tightly embedded in the copper matrix as a lubricating phase,which significantly improved the friction and wear pro-perties of the composite.The friction and wear mechanism of composites were mainly abrasive wear,adhesive wear and oxidative wear.