Core–shell Si3N4@WS2 porous ceramics with improved electromagnetic wave absorption performance.

Ceramic-based absorbing materials have attracted extensive attention in electromagnetic wave (EMW) absorption because they are lightweight and exhibit strong dielectric loss. However, there is still a need for developing the microstructure design of ceramics, and this hinders the further improvement of absorption properties. In this study, core–shell Si₃N₄@WS₂ porous ceramics, with the wave-transmitting phase Si₃N₄ as the core and the wave-loss phase WS₂ as the shell, were prepared using a simple impregnation-hydrothermal method. The core–shell structure provided as large a contact area as possible between WS₂ and Si₃N₄, promoting the formation of heterogeneous interfaces. The as-prepared core–shell Si₃N₄@WS₂ porous ceramics exhibited excellent EMW absorption properties. When thickness was 3.92–4.22 mm, an effective absorption bandwidth of 4.20 GHz was achieved, covering the entire X-band (8.2–12.4 GHz). At a thickness of 4.35 mm, the minimum reflection loss was −65.03 dB. The outstanding EMW absorption performance was attributed to the special core–shell microstructure inducing interfacial polarization loss and optimizing the impedance matching of the material. The findings of this study provide novel insights and feasible strategies for designing ceramic-based absorbing materials with core–shell structures. [ABSTRACT FROM AUTHOR]