High Thermal Conductive Composite Containing a Network of Vapor Grown Carbon Fiber and Carbon Nanotube in Aluminum Matrix

Abstract

In this paper, high thermal conductive composites are developed for the cooling device of Insulated Gate Bipolar Transistors (IGBT) for aerospace. The composite is fabricated by Spark Plasma Sintering (SPS) from aluminum powder and vapor grown carbon fiber (VGCF). The 10wt% of aluminum-silicon alloy is added to the aluminum powder for the improvement of the interface adherence between VGCF and aluminum. Carbon nanotube (CNT) is also dispersed on VGCF fillers for further improvement of the thermal conductivity of the composite. As a result, the composites fabricated have about three times higher thermal conductivity than the pure aluminum. Especially, a small amount dispersion of CNT into VGCF leads to the large improvement of the thermal conductivity. Analyses of finite element method (FEM) are conducted to understand mechanisms of the improvement of thermal conductivity by the dispersion of CNT. The FEM analysis shows that VGCF-CNT networks play important roles for the improvement of the thermal conductivity.