Effect of ChromiumAdditions on the Thermal Conductivity of Diamond Particle Dispersed Cu Matrix Composites Fabricated by SPS

Diamond-particle-dispersed-copper (Cu) matrix composites were fabricated by spark plasma sintering (SPS) process from the mixture of diamond particles, pure-Cu and boron (B) powders. The microstructures and thermal conductivities of the composites fabricated were examined. These composites were all well consolidated at a temperature of 1173 K for 600 s by spark plasma sintering (SPS) process. No reaction at the interface between the diamond particle and the Cu matrix was observed by scanning electron microscopy and X-ray diffraction analysis for the composites fabricated under the sintering condition employed in the present study. The relative packing density of the diamond particle dispersed Cu matrix composites with B addition was 3.5~6.1 % higher than that without B addition. The thermal conductivity of the Cu/diamond composite drastically increased with B addition. The thermal conductivity of (Cu-B)-50 vol% diamond composites was 594~689 W/mK in a volume fraction range of B between 1.8 and 13.8 vol% in Cu matrix. Numerous transgranular fractures of diamond particles were observed on the bending fracture surface of diamond particle dispersed Cu matrix composites with B addition, indicating strong bonding between the diamond particle and the Cu matrix in the composite.