Gang-Hui Guan, Xiao-Ping Zhou
Addressing the growing issue of electromagnetic pollution and the challenges associated with the insufficient oxidation and corrosion resistance of traditional electromagnetic wave-absorbing materials, a strategy is proposed to incorporate EGaIn with FeCoNi medium-entropy alloy particles. Core–shell structured FCN@LM microwave-absorbing materials are successfully fabricated via a mechanical grinding method, and their microstructures, electromagnetic properties, and absorption mechanisms are systematically investigated. The results demonstrate that an appropriate amount of LM coating (5 wt%) effectively constructs heterogeneous interfaces, enhances interfacial polarization and conduction loss, and significantly improves impedance matching and attenuation capability. The composite achieves a minimum reflection loss of −63.69 dB at a thickness of 1.95 mm and an effective absorption bandwidth of 6.56 GHz. The charge transfer mechanism at the interface is elucidated through density functional theory (DFT) and surface potential measurements, while radar cross-section (RCS) simulations further confirm its excellent radar stealth performance. This study offers new insights for the design of high-performance and corrosion-resistant microwave-absorbing materials.