Evaluation analysis of electromagnetic wave absorption for self-assembled 3D graphene skeleton-supported BN/SiC composites

In this work, a high-performance electromagnetic wave (EMW) absorber is prepared by the in situ growth of BN and SiC into a self-assembled 3D graphene skeleton via chemical vapor infiltration (CVI). The porous conductive graphene network extends the transmission path of incident microwaves by multiple scattering, and the ceramic coating effectively improves the impedance matching degree. Notably, the EMW absorbing performance of 3D-rGO/BN/SiC can be regulated by the high-temperature oxidation in air. Compared to the original absorbers, after being oxidized at 600 degrees C for 4 h in air, the optimal RLmin of the composites drops to -47.1 dB and the broadest EAB reaches 11.96 GHz, which can be attributed to the enhanced impedance matching degree. The controllable fabrication of 3D-rGO/BN/SiC composites can provide a guideline for rational design and fabrication of high-performance EMW absorbing materials in practical applications under medium oxidizing temperature. A 3D-graphene/BN/SiC microwave absorber with a hierarchical structure is prepared, whose absorbing performance can be easily regulated by oxidizing in air.