The Research Of Copper Alloy/graphite Composites

Copper alloy/graphite composite is composed of copper alloy matrix andgraphite particles, it has high strength, fast thermal conductivity, good electricalconductivity, good lubricating performance and other excellent properties of coppermatrix and graphite. In order to improve the mechanical properties and wearperformance of composite, the wettability between copper alloy and graphite particlesmust be improved. In this article the graphite particles first were coated with uniformNi-B coatings using an electroless plating method, then copper alloy/graphitecomposites were prepared by powder metallurgy process. The coated graphiteparticles were characterized by scanning electron microscopy (SEM), X-raydiffraction (XRD), transmission electron microscopy (TEM). The mechanicalproperties, density, friction and wear performance were investigated, we also studythe influence of the graphite content and Ni-B coatings on the properties above. Thecrack propagation and wear mechanism of the composites were also illustrated.The results show that the composites with Ni-B coated graphite exhibited higherdensity, hardness and compression strength comparing with those of composites withbare graphite. The relative density was increased by0.86-2.46%, the hardness wasincreased by2.2-5.4%, the compression strength was increased by20.8%whengraphite content is2%, the coefficient of friction was decreased by9-16%. By theanalysis of crack propagation and wear mechanism, Ni-B coatings could improvebonding strength between graphite and matrix and block crack propagation duringcompression process; The wear mechanism of copper alloy/graphite compositesmainly contained adhesive wear and abrasive wear. This study provided importanttheoretical foundation and scientific basis for the preparation and research of newcopper alloy/graphite composite.