Thermal conductivity and mechanical properties of flake graphite/Al composite with a SiC nano-layer on graphite surface

The graphite/Al composites with SiC coated on graphite surface (graphite-SiC/Al) were fabricated by vacuum hot pressing technology. The microstructures and interfaces of graphite-SiC/A1 composites were studied and the effect of SiC coated on graphite surface on thermal conductivity and bending strength were investigated. The results showed the 250 nm SiC layer was formed during coating process and this interlayer inhibited the formation of Al4C3. The thermal conductivity of the graphite-SiC/Al composite in x-y plane direction increased from 528 to 735 W/m K as the volume fraction of the graphite increased from 40 to 70%. The introduction of nano SiC layer indeed improved the interfacial thermal conductance and thus increased the thermal conductivity of the composites. The bending strength of graphite/Al composites were significantly enhanced after SiC coated and the maximum bending strength was 90 MPa when the volume fraction of graphite was 40%. The fracture mechanism and the reasons for the improvement of bending strength were deeply discussed in this study. (C) 2016 Elsevier Ltd. All rights reserved.