Interfacial microstructure of copper/diamond composites fabricated via a powder metallurgical route

The interfaces in Pulse Plasma Sintered composites of Cu0.8Cr and diamond have been characterised. The interfaces between the diamond and the Cu0.8Cr matrix generally exhibited a strong degree of bonding, but variations related to the orientation of the diamond facets were revealed. Image analysis established that the surfaces of the diamond particles were partially coated with chromium carbide, which averaged 43% for the {111} facets and 31% for the {100} facets. In addition thin and irregular layers of graphite were also observed. The composite with a 50% volume fraction of diamond possessed a thermal diffusivity of 218 mm2/s which infers a thermal conductivity of 589 W/(m·K), which is 76% of the maximum theoretical conductivity predicted by the Maxwell model.