Highly thermoconductive copper-graphite flake composites controlled in the heat direction by electroless plating and spark plasma sintering

Abstract

The miniaturization and high performance of electronic components has increased the amount of heat generated by these devices. Copper (Cu)/carbon composites are gaining attention as heat sink material; however, these composites are limited by the weak interface bonding. To overcome these problems, Cu was deposited on a graphite flake (GF) surface by electroless plating to increase interfacial bonding between Cu and graphite, and the composite materials were then consolidated by spark plasma sintering. The Cu content was varied from 20 to 60 wt% to investigate the effect of the graphite fraction and microstructure on the thermal conductivity of the composites. For 40 wt% Cu/GF composites, the thermal conductivity obtained experimentally was as high as 692 W/m·K, and the coefficient of thermal expansion was 4.12 ppm/K. Cu/GF composites show potential for heat dissipation applications in energy storage and electronics, due to their high thermal conductivity and low thermal expansion coefficient. • Cu/GF composites were prepared by electroless plating and spark plasma sintering. • The orientation of GFs in the composites to the heat flow direction was controlled. • The interfacial bonding between Cu and GF was improved by oxygen functional groups. • The thermal conductivity of 40 wt% Cu/GF composites was highest at 692 W/m·K. • The outstanding thermal properties due to the formation of thermal pathway of GFs.