<i>In Situ</i> Combustion Synthesis of Gr/<i>h</i>-BN Composites and Its Passive Heat Dissipation Application

Abstract

To enhance the infrared radiation efficiency and the heat transfer performance simultaneously, graphene (Gr) was synthesized <i>in situ</i> on hexagonal boron nitride (<i>h</i>-BN) to prepare Gr/<i>h</i>-BN composites by a scalable combustion synthesis in CO₂ atmosphere using Mg as sacrificial solder. The synthesized Gr/<i>h</i>-BN composites were added in polydimethylsiloxane polymer to prepare composite coatings, which show an infrared emissivity greater than 0.95 and a through-plane thermal conductivity up to 2.584 W·m^-1·K^-1. When functioning on an Al heatsink, such a composite coating can reduce the temperature by as much as 21.7 °C. Meanwhile, the composite coating exhibits superior adhesion on the Al substrate. Therefore, Gr/h-BN composite coatings with noteworthy infrared radiation and thermal conductivity are expected to be a promising candidate for heat dissipation applications.