Influence of sputtering and electroless plating of Cr/Cu dual-layer structure on thermal conductivity of diamond/copper composites

Highly uniform, dense and tightly-bonded Cr/Cu dual-layer films are successfully deposited on the surface of diamond particles combined with magnetron sputtering and electroless plating. Then, Cr/Cu-coated diamond particles and Cu powders are utilized to synthesis diamond/Cu composites by the spark plasma sintering. Scanning electronic microscope, transmission electron microscope and optical microscope are employed to examine the structure and morphology of the as-prepared diamond/Cu composites. The results reveal the formation of an interfacial zone between diamond particles and Cu matrix, which is mainly composed of Cr-Cu-C. One should note that the growth of interlayer mainly depends on the electro-plating time. Moreover, a laser thermal conductivity meter is employed to measure the thermal conductivity (TC) of diamond/Cu composites, reaching a value of 613 W/m·K due to the formation of an excellent interface between diamond particles and Cu matrix. The diamond/Cr-C/Cr/Cr-Cu/Cu interface structure can significantly decrease the interface thermal resistance and, in turn, enhance the thermal conductivity.