Study on properties of graphite oriented copper-based friction materials
SHI Yong-liang1,ZHAO Xiao-ping1,CHEN Cun-guang2
1 Department of Materials Engineering,Hebei College of Industry and Technology,Shijiazhuang 050091, China; 2Advanced Material and Technology Institute,University of Science and Technology Beijing,Beijing 100083,China
Abstract:Copper-based friction materials with oriented distribution of flake graphite were prepared by cold-pressing and hot-pressing sintering process with Al2O3 dispersion-strengthened copper powder as matrix and copper-plated flake graphite as lubricating phase. The distribution of flake graphite in copper matrix was observed by scanning electron microscopy,and the density,hardness,compressive strength,thermal conductivity and friction properties were tested and analyzed. The results show that the flake graphites are distributed uniformly in the copperbased friction material,and have good bonding between copper matrix. The graphite sheet tends to be perpendicular to pressing direction. The vertical compaction direction have higher hardness and compressive strength than the compaction direction. The thermal conductivity of the vertical compaction direction is three times higher than that of the compaction direction,and the friction coefficient,wear rate and friction surface temperature of the vertical compaction direction are lower than that of the compaction direction at high flake graphite volume fraction.