MOF composite FeSiB-based nano-amorphous magnetic powder and the influence of porous morphology on dielectric polarization and microwave absorption mechanisms

FeSiB-based nano-amorphous soft magnetic alloy composites have excellent wave-absorbing properties which are among the most promising high-performance wave-absorbing materials. FeSiBNbCu nano-amorphous soft magnetic alloy micropower was used as the matrix. Fe-based (MIL-101(Fe)) porous materials were grown on the lamellar amorphous surface by in situ composite method, which successfully prepared FeSiBNbCu@MIL-101(Fe) magnetic alloy micropower with excellent wave-absorbing properties. The porous nature of the MOF materials, enhanced interfacial polarization and multiple reflections and scatterings of the composites, and thus significantly improved microwave absorption properties of the materials. Furthermore, the introduction of the MOF materials reduced the electrical conductivity of the materials and optimized the impedance matching. The reflection loss minima (RLmin) of the composites reached -71.29 dB (d= 4.4 mm, f=4.74 GHz) and -63.23 dB (d= 2.4 mm, f=10.35 GHz) at 10 wt% and 20 wt% MIL-101(Fe), respectively, and the effective absorption bandwidths, of RL <= - 20 dB (1.4 GH and 1.3 GHz), are broadened obviously in the range of d=2.5 mm similar to 3.5 mm.