Effects of Sintering Process on Microstructure and Properties of Flake Graphite-Diamond/Copper Composites

Flake graphite-diamond/Cu-Cr-Zr composites with good two-dimensional thermophysical properties were prepared by vacuum hot-pressing technology. The influence and working mechanismof the hot-pressing temperature on the relative density and thermal conductivity of the composites were studied to obtain the optimum sintering process. The results showed that with a pressing pressure of 10 similar to 20 MPa, the relative density and thermal conductivity of the composite materials increased as the sintering temperature increased from 950 to 1010 degrees C. When the temperature rose to 1010 similar to 1040 degrees C, a near fully dense composite material was obtained and thermal conductivity reached maxima of 410 and 119 W/mK parallel and perpendicular to the graphite planes, respectively, both of which are close to the theoretical value. However, relative density and thermal conductivity drastically decreased as the temperature continued to increase beyond 1070 similar to C. This is attributed to the combined effect of sintering temperature and wettability between the matrix and the reinforcements.