Bioinspired highly oriented SiC nanowire arrays for microwave absorption and thermal insulation

Silicon carbide nanowires (SiCnws) with high dielectric loss and superior thermal stability attract increasing attention in the field of microwave absorption and thermal insulation. However, the low dielectric constant and no magnetic loss limit their broad application. In this study, a bioinspired highly oriented SiC nanowires arrays with a gradient structure were fabricated on carbon fiber cloth by catalyst-assisted chemical vapor deposition method, showing excellent performance in both microwave absorption and thermal insulation. It was found that the microwave absorption properties were closely related with the metallic catalysts and the SiCnws arrays prepared with Co(NO₃)₂ as the catalyst had a strong microwave absorption capacity. When the thickness was 1.35 mm, the effective absorption bandwidth was 4.59 GHz (13.41–18 GHz), and the minimum reflection loss (RL_min) reached −37.92 dB at the thickness of 3.10 mm. Meanwhile, the bioinspired oriented SiC nanowires arrays also had excellent thermal insulation and heat preservation effects, making them potential candidates for heat insulation applications. This study not only provides a simple and universal preparation method for oriented SiCnws arrays on carbon fibers, but also offers new research ideas for the wide applications of SiCnws in microwave absorption and thermal insulation.