Enhanced microwave absorption of core-shell SiC@Cr-Si-C absorber fabricated by facile molten salt synthesis

SiC, with outstanding oxidation stability and tunable dielectric property, has been regarded as a promising microwave absorption material for high-temperature applications. However, the application of pristine SiC is restricted by its inadequate dielectric response and weak loss capability. Herein, a novel strategy is proposed to construct Cr-Si-C conductive shell on SiC surface via molten salt method is proposed to introduce heterogeneous interfaces and enhance dielectric loss. The optimal SiC@Cr-Si-C core-shell sample achieves a minimum reflection loss (RL_mᵢ_n) of −36.7 dB at a matching thickness of 1.4 mm. Meanwhile, it exhibits an effective absorption bandwidth (EAB) of 2.41 GHz. Notably, even after heat treatment at 600 °C in air for 5 h, the core-shell absorber maintains an intact core-shell structure and its RL_mᵢ_n remains as high as −34.4 dB, demonstrating superior high-temperature stability. This work provides an effective method for high-performance microwave absorption materials targeted at high-temperature applications.