High thermal conductivity diamond/SiC fibers/EP insulant composites with low permittivity prepared at different temperatures

Abstract

Electronics require advanced encapsulating materials with high heat dissipation efficiency, low dielectric properties, and high insulating properties. Although epoxy (EP) composites have excellent insulation, dielectric properties, and mechanical strength, their low thermal conductivity still hinders their wide application. Herein, an innovative diamond/SiC fibers/EP insulant composite was prepared by depositing diamond onto the three-dimensional silicon carbide fibers (3D SiCs) fabric via microwave plasma chemical vapor deposition. A dense and continuous 3D diamond/SiC fiber with various crystal sizes was prepared by varying the deposition temperature. Subsequent vacuum-assisted impregnation with EP resin, followed by a curing process, produced a novel diamond/SiC fibers/EP composite material. The (Dia/SiCs)800/EP composite achieved a thermal conductivity of 0.74 W m−1 K−1 at 30 °C, which was 353.3% higher than that of pure EP resin (0.17 W m−1 K−1 at 30 °C). Meanwhile, the dielectric constant and volume resistivity of the (Dia/SiCs)800/EP are 3.79 at 100 Hz and 2.84 × 1013 Ω cm, demonstrating outstanding dielectric and electrical insulation properties. In thermal response tests, the surface temperature was 16.6 °C lower than that of pure EP resin. Finally, theoretical analysis indicated that the 3D diamond/SiC fibers framework is the efficient heat transfer path within the diamond/SiCs/EP composites. This work presents a straightforward and effective strategy for fabricating high-performance, multifunctional EP composites with significant application potential in advanced electronic encapsulation.