Enhanced mechanical and wave‐absorption properties of SiC–Si3N4–FeSi porous ceramics by introducing Al

Abstract SiC‐based porous ceramic wave‐absorbing materials have attracted much attention due to their excellent properties such as low density, high‐temperature resistance, and oxidation resistance. In this work, the impedance matching of SiC ceramics is improved by introducing Si 3 N 4 wave‐transparent phase, and the dielectric loss capability of SiC ceramics is enhanced by introducing FeSi wave loss phase. To achieve a balance between impedance matching and absorption loss in porous ceramics, different molar contents of Al were introduced into FeSi to tailor electromagnetic parameters. The effects of introducing FeAl x Si 1− x on the phase composition, microstructure, dielectric loss, and microwave absorption mechanism of SiC–Si 3 N 4 porous ceramics were systematically investigated. When FeAl 0.25 Si 0.75 is added, the minimum reflection loss of the porous ceramics is as low as −58.02 dB, and the flexural strength is as high as 87.23 MPa. The presence of Al promotes the transformation of the Si 3 N 4 crystal and the generation of Al 2 O 3 . The introduction of FeAl 0.25 Si 0.75 into SiC–Si 3 N 4 has constructed “inductor–capacitor–resistance” microcircuit, which enhances polarization loss, conductivity loss, and magnetic loss, and realized the double enhancement of the mechanical and wave‐absorbing properties of porous ceramics.