Hollow silicon carbide microspheres for excellent and lightweight electromagnetic wave absorber

Abstract

Developing semiconductor ceramic materials with lightweight, outstanding stability, and high-performance electromagnetic wave (EMW) absorption are attractive for harsh environments. Due to thermal and chemical stability, designable microstructure, and tunable dielectric property, microstructured silicon carbide (SiC) ceramics offer promising potential as excellent EMW absorbers while limited by the scarce fabricating methods. Here, a simple coaxial electrospinning technology and the high-temperature calcination process are developed for the first time to fabricate hollow SiC microspheres (HSCMs) for EMW absorbers. Owing to the sizeable SiC-free space interface in the shell and internal void, the inner hollow structure also endows HSCMs with excellent EMW absorbing properties. By comparing with the composite of 40 wt% solid SiC microspheres (SSCMs)/paraffine, it is found that the 40 wt% HSCMs/paraffin composite exhibits superior dielectric properties and a minimum reflection loss (RL) value of − 61.6 dB at 7.7 GHz and 3.4 mm thickness, associated with the most considerable adequate absorption bandwidth of 4.9 GHz (from 12.6 to 17.5 GHz) at 1.9 mm thickness. This work gives rise to a handy method for fabricating hollow SiC with lightweight and high-efficiency EMW absorption. It will potentially boost the development of next-generation EMW absorbers for harsh environment applications.