Advances in Fe-based electromagnetic wave absorbers: Multiscale engineering from atomic defects to macroscopic architectures for performance optimization

The rapid development of electronic devices and communication technologies has resulted in increasingly severe electromagnetic-wave (EW) pollution. Efficient EW absorption (EWA) materials are essential to mitigate their impact and ensure human safety in modern society. Fe-based EWA materials have garnered significant attention owing to their cost-effectiveness, high saturation magnetization, and superior magnetic loss capabilities. This review begins with an introduction to Fe-based EWA materials, followed by a brief description of their EWA mechanisms. Various pristine Fe-based absorbers, such as carbonyl iron powder, ferrite-based materials, Fe-based alloys, Fe-based high-entropy alloys (HEAs), and Fe-based layered ternary transition-metal borides, have been systematically reviewed. Key strategies to enhance the performance of Fe-based composite absorbers, including doping, in-situ oxidation, porous structuring, and composite construction, are critically discussed. Finally, the review presents a summary and future perspectives in this field, highlighting the synergy between Fe-based and high-entropy materials in advancing next-generation EWA for applications in stealth technology, wearable electronics, and harsh environments.