Effects of dual-layer coatings on microstructure and thermal conductivity of diamond/Cu composites prepared by vacuum hot pressing

Abstract

Diamond/Cu composites with high density and good thermal properties are fabricated by vacuum hot pressing via designing dual layers on the diamond particles. Different types of inner tungsten layers are coated on diamond after annealing with the loose tungsten powder, and the outer copper layer is then deposited using electroless plating. The effects of dual layers on the microstructure and thermal conductivities of diamond/Cu composite are investigated. The results indicate that the tungsten coating exhibits integrated and uniform structure when the diamond is treated with tungsten powder at 900°C for 2h. This tungsten coating improves the interfacial bonding and minimizes the thermal boundary resistance between the diamond and the copper matrix. Moreover, the outside copper coating promotes the sintering process, and hence favors the low-temperature densification of diamond/Cu composites. The thermal conductivity of diamond/Cu composites reaches 721Wm−1K−1, which is close to the theoretical value.