Lightweight porous NiCo-SiC aerogel with synergistically dielectric and magnetic losses to enhance electromagnetic wave absorption performances

Abstract

Microwave absorption performances can be remarkably enhanced using an electromagnetic (EM) wave absorber with synergistically dielectric and magnetic losses. In this study, the eggplant was used as a raw material to produce silicon carbide (SiC) aerogel by two steps: carbonization and subsequent carbothermic reduction. Then the magnetic NiCo layer was coated on the SiC aerogel (NiCo–SiC) by chemical plating method. The NiCo-SiC aerogel with an extremely low density (0.194 g/cm3) primarily composed of a porous SiC skeleton, SiC nanowires, and the magnetic NiCo alloy nanoparticles distributed on SiC skeleton and nanowires surfaces. The existence of magnetic NiCo alloy nanoparticles in the aerogel, the magnetic and dielectric losses are both increased by the formed heterogeneous interfaces. Thus, the NiCo–SiC aerogel with a thickness of 3 mm exhibits a minimum reflection loss (RLmin) of − 44.5 dB and an effective absorption bandwidth (RL<−10 dB) of 7.6 GHz, which displays the potential application in lightweight and excellent EM wave absorbers.