Enhanced thermal conductivity in diamond/aluminum composites with a tungsten interface nanolayer

A tungsten (W) nanolayer was first introduced onto diamond particles by a sol–gel process, and then aluminum (Al) based composites were fabricated by vacuum hot pressing using the W coated diamond (diamond@W) particles. The microstructure of the W nanolayer and its effect on the thermal properties were explored. The results showed that the W nanolayer with a dendritic morphology and a thickness of 200 nm is the optimum combination to improve the interfacial bonding and minimize the thermal boundary resistance between diamond and Al. Such an observation was explained by the tunable formation of trace amount of W2C. The thermal conductivity of 50 vol.% diamond@W/Al composites was 599 W/mK, 21% higher than that of the composite without the W interface nanolayer. Our results were found to be in good agreement with the theoretical predictions by the combined differential effective medium (DEM) and acoustic mismatch model (AMM) schemes.