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

• Published in: Journal of materials science & technology 2023-01, Vol.132, p.90-99
• Main Authors: Li, Wanjia, Li, Wangchang, Ying, Yao, Yu, Jing, Zheng, Jingwu, Qiao, Liang, Li, Juan, Che, Shenglei
• Format: Article
• Language: English
• Subjects: Fe/Fe4N@SiO2; Flower-like core-shell structure; Multifunctions; Ultrathin microwave absorber
• ISSN: 1005-0302; 1941-1162
• DOI: 10.1016/j.jmst.2022.05.045

•A multifunctional flower-like core-shell Fe/Fe4N@SiO2 composites with broadband and high-efficiency microwave absorption were investigated. The RLmin value reached –71.31 dB at the matching thickness of 1.4 mm, and the EABmax value is 6.1 GHz when the matching thickness is 1.16 mm.•The flower-like core-shell structure and the Fe/Fe4N heterointerface increase the interface polarization and multiple scattering effects, and the multiple resonance modes of Fe and Fe4N lead to increased broadband and multi-band magnetic losses at high frequencies, improving impedance matching and electromagnetic wave absorption effects.•This nanocomposite absorber is suitable in harsh application environments for the excellent corrosion resistance and high temperature resistance. 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/Fe4N@SiO2 nanomagnetic core-shell materials with different Fe/Fe4N ratios by performing nitridation reactions at different temperatures. Then, the flower-like core-shell Fe/Fe4N@SiO2 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. The flower-like core-shell structure and the Fe/Fe4N heterointerface increase the interface polarization and multiple scattering effects, and the multiple resonance modes of Fe and Fe4N lead to broadband and multi-band magnetic losses at high frequencies. [Display omitted]