Hollow porous SiC spheres prepared by in-situ reaction with efficient microwave absorption

The microscopic morphology and structure design of absorbent materials are critical concerns in microwave absorption. The adjustment of morphology and structure can significantly affect absorbing properties. In this work, the hollow porous SiC spheres (HPSS) are prepared by simple self-assembly technology and in-situ reaction (ISR). The results show that the particle size and the shell thickness of HPSS can be controlled by changing the temperature. The special hollow porous structure improves the impedance matching of HPSS and exerts a substantial impact on absorption performance. HPSS being different temperature displays different electromagnetic wave (EMW) absorption properties. Especially, when the temperature reaches 1550 °C, the minimum reflection loss (RL_min) value reaches −51.35 dB and the maximum effective absorption bandwidth (EAB_max) is 5.43 GHz at 2.08 mm. The excellent property is ascribed to the synergetic effect of good impedance matching and strong dielectric loss brought by HPSS. This work not only provides an approach to designing special hollow porous structures by ISR but also offers instruction for the effect of the morphology and structure on microwave absorption.