Hollow Sic Microtube With Multiple Attenuation Mechanisms For Broadband Electromagnetic Wave Absorption

The hollow SiC microtubes were designed and prepared by the de-template of SigCF coaxial materials to enhance the electromagnetic wave absorption bandwidth of the SiC materials. The XRD, Raman, and TEM results indicated that the hollow SiC microtubes were composed of SiC, C, and amorphous SiO2 layers. The carbon particles uniformly embedded in the SiC particles and the amorphous SiO2 covered the outside of the SiC microtube. The dielectric properties of the hollow SiC microtube could be optimized by controlling its wall thickness. The hollow SiC microtube showed a broader electromagnetic wave absorption bandwidth compared to that of other SiC materials. The minimum reflection loss of hollow SiC microtube was -25.7 dB@14.9 GHz, and the effective absorption bandwidth was 5 GHz covering from 12.9 GHz to 17.9 GHz at a sample thickness of 2 mm. The uniform distribution of carbon contributed to improving the conduction loss of hollow SiC microtube. The interfacial relaxation loss causing by the outermost SiO2 layer enhanced the dielectric loss of the tubular SiC. Besides, the unique hollow structure of the SiC microtube significantly promoted the multi reflection and scattering of electromagnetic waves. The multiple attenuation mechanisms of tubular SiC highlighted the design of a novel structure for a high-performance electromagnetic wave absorber. (C) 2020 Elsevier B.V. All rights reserved.