Fabrication of diamond/aluminum composites by vacuum hot pressing: Process optimization and thermal properties

Diamond/Al composites were prepared by vacuum hot pressing (VHP) to get high thermal properties. The sintering temperature, pressure and time in the VHP process were optimized. Microstructures, thermal properties, interface reaction product and its effect on the properties of the composites were investigated. The result shows that the sintering temperature and time are key parameters to get high thermal property of the composites. The composites with 20-55 vol% diamond sintered at 650 °C for 90 min under a pressure of 67 MPa exhibit thermal conductivities of 320-567 W/mK, over 90% of the theoretical predictions by the differential effective medium (DEM) scheme. The high thermal conductivity is attributed to the favorable interface conductance, while the formation of aluminum carbide at diamond-Al interface is found to be negative.