Designing insulative SiC coating layer on the artificial graphite particle to achieve synergy of wave absorption and thermal conduction

Artificial graphite powders possess attractive intrinsic thermal conductivity (TC) and sphericity for a high loading, but their poor electrical insulation hinders the electromagnetic wave (EMW) absorption for applying in the field of electronic packaging. Herein, the spherical artificial graphite coated by insulating silicon carbide (SG@SiC) layer with integrated functionalities of outstanding EMW absorption and excellent TC are synthesized via a facile gas-solid chemical reaction. The surface of the prepared SG@SiC particles features abundant nanometer-sized pores that facilitates to regulate impedance matching, which favors to realize superior EMW absorbing performance. Interfacial polarization introduced by the core-shell structure and inherent conduction loss are more conducive to elevating the EWM-absorbing of SG@SiC. The SG@SiC composites achieve a TC of 3.28 W m−1 K−1 at a loading of 73.7%, which increases 16.2 times higher than initial silicone rubber (SR). In addition, the SG@SiC composite demonstrated exceptional wave-absorbing properties with a minimum reflection loss (RLmin) of −31.9 dB at a frequency of 7.9 GHz and an effective absorption bandwidth (EAB) of 2.9 GHz under the thickness of 2.0 mm. Given these superior properties, the versatile SG@SiC composites open up an avenue to integrate EMW absorption and thermal evacuation in a single component for electronic packaging applications.