Construction of C-Si heterojunction interface in SiC whisker/reduced graphene oxide aerogels for improving microwave absorption

The SiC/graphene aerogels have been widely studied in microwave absorption, but the influence mechanism of SiC microwave absorption was not clear. Herein, we prepared the SiC whiskers/reduced graphene oxide aerogels (SiCw/rGOA) by in-situ growth (IS) and physical mixing (PM) methods and investigated the influence of the C-Si heterojunction on microwave absorption performance. The results show that the incorporation of SiCw can improve the interfacial impedance between free space and absorber compare to the pure rGOA, resulting in the excellent microwave absorption property. The polarization loss induced by defects and interfaces is an important factor for microwave attenuation. Especially, the formation of the C-Si heterojunction interface between SiCw and reduced graphene oxide in SiCw/rGOA-IS enhances the polarization loss at low frequency (2-6 GHz). The minimum reflection loss (RL) value of SiCw/rGOA-IS reaches to -60.05 dB at 17.12 GHz with a thickness of 2.00 mm, and its effective absorption bandwidth (EAB, below -10 dB) is up to 6.72 GHz, covering whole Ku band. Furthermore, this as-prepared absorbing material exhibits excellent mechanical and thermal properties after compound with polydimethylsiloxane. (C) 2020 Elsevier Ltd. All rights reserved.