Effects of diamond particle size on the formation of copper matrix and the thermal transport properties in electrodeposited copper-diamond composite materials

Abstract

Electrodeposition is considered as a cost-effective fabrication method for metal-diamond heat sink materials. However, the formation of the metal-diamond interface has not been addressed in detail to date although controlling the interfacial microstructures is crucial. In this study, we electrodeposited copper-diamond composite materials and observed that 66 μm sized diamond particles decreased the thermal conductivity of copper whereas 420 μm sized diamond particles increased the thermal conductivity. The differential effective medium (DEM) model analysis showed that the thermal boundary conductance values at the electrodeposited copper matrix-diamond interface were 1.3 MW/m2K and 3.1 MW/m2K when the diamond particle sizes were 66 μm and 420 μm, respectively. This discrepancy was attributed to the microstructure of the copper matrix in the vicinity of diamond particles, which was caused by particle size dependent current density distribution. These results show that particle size in electrodeposited composite materials can strongly affect the microstructure of the metal matrix.