Fabrication of core-shell Fe4N@C with sea-island structure by one-step nitriding method as efficient electromagnetic wave composite absorber

Porous structure design and magnetic-dielectric composite are effective ways to develop electromagnetic wave (EMW) absorbing materials with light-weight, thin-thickness, large effective absorption bandwidth (EAB), and strong reflection loss (RL). This article presents a simple one-step nitridation method for synthesizing Fe 4 N@C compounds with sea-island like and core-shell structures. The optimal RL value of Fe 4 N@C is up to −60.01 dB, and the EAB (frequency range for RL< −10 dB) is 5 GHz (11.1–16.1 GHz) with a thickness of 1.9 mm. The EAB reaches 5.5 GHz (12.5–18 GHz) when the matching thickness is 1.7 mm. The multi-component design achieved excellent impedance matching properties. The carbon frame connects the core-shell particles to form a three-dimensional porous structure, providing multiple reflection losses. Therefore, this work provides a convenient way to design efficient and lightweight EMW absorbers with special structures.