Multifunctional flower-like core-shell Fe/Fe4N@SiO2 composites for broadband and high-efficiency ultrathin electromagnetic wave absorber

The nano-iron nitride soft magnetic material has excellent magnetic properties and is expected to be a brilliant electromagnetic wave absorber. However, how to fully exploit its wave-absorbing potential remains a thought-provoking question. Here, we have synthesized Fe/Fe4[email protected]2 nanomagnetic core-shell materials with different Fe/Fe4N ratios by performing nitridation reactions at different temperatures. Then, the flower-like core-shell Fe/Fe4[email protected]2 structure was obtained by the etching method. Finally, with the synergy of the excellent magnetic and dielectric losses, an outstanding absorption performance could be achieved with a minimum refection loss (RLmin) of −71.31 dB at the matching thickness of 1.4 mm, and the widest effective absorption bandwidth (EABmax) of 6.1 GHz less than −10 dB was realized at 1.16 mm. Moreover, this material also shows a preeminent advance in corrosion resistance to adapt to harsh environments. Hence, this iron nitride flower-like core-shell structure exhibits great potential in microwave absorption in harsh conditions.