Effect of surface roughening on the interfacial thermal conductance of diamond/copper composites

Understanding the mechanism of interfacial heat transfer is the key to improved thermal conductivity of diamond/copper composites. Diamond particles are etched via molten salt to obtain different surface roughness and are subsequently coated with dual layers of tungsten and copper (Cu). Then, diamond/Cu composites are prepared by hot pressed sintering. When the (111)(D) surface roughness of the diamond is 11.1 mu m, a maximum thermal conductivity of 602 W.m(-1).K-1 is obtained, which is 12% higher than that of un-etched diamond/Cu composites. The roughness significantly increases the coupling area between the diamond and the Cu matrix, providing more heat transfer channels and a secondary heat transfer process at the diamond/matrix interface. The preparation of the high-thermal-conductivity composites is thus enhanced by controlling the surface roughness of the diamond particles.