A hierarchical SiCnw@SiC aerogel decorated with Ni-capped carbon nanotubes toward high-performance electromagnetic wave absorber

Abstract

Increasing attention has been paid to the regulation of electromagnetic parameters by reasonable micromorphological design and proper composition to realize high-performance electromagnetic wave absorbers. Herein, a unique hierarchical SiC nanowire-reinforced SiC aerogel decorated with Ni-capped carbon nanotubes (SiCnw@SiC-Ni@CNT) was constructed. The effective synergism between the combination of multiphase magnetic/dielectric materials and the introduction of specific 3D hierarchical microstructures is beneficial for the apparent improvement of multiple dielectric/magnetic losses, electromagnetic scattering effects, and impedance matching capabilities, exhibiting remarkable tunable microwave absorption performance. Accordingly, a strong microwave absorption intensity (RLmin) at 10.24 GHz of −47.75 dB with a loading of 20 wt% and an ultrawide effective absorption bandwidth (EAB, RL < −10 dB) of 8.96 GHz (9.04–18.0 GHz) at only 30 wt% filler loading and thin 2.0 mm thickness are realized. This work provides valuable guidance for the design of multiphase magnetic/dielectric absorbers with hierarchical microstructures and extends the study of advanced microwave absorption materials with the advantages of light weight, minimal thickness, strong RL and broad EAB.

Keywords

• SiC aerogel
• Ni nanoparticles
• Carbon nanotubes
• Hierarchical microstructure
• Microwave absorption