Optimization of microwave absorption properties of flaky FeSiAl magnetic alloy by surface modification

The surface modified flaky FeSiAl magnetic microwave absorbing material was prepared by controlled oxidation heat treatment, and was compounded with MOFs (Metal Organic Frameworks) material. The dielectric polarization characteristics and the microwave loss mechanism for the heterogeneous structure are analyzed. The obtained MOFs@FeSiAl balances the electromagnetic wave attenuation ability and the impedance matching, thus achieving excellent microwave absorbing properties. The effective absorption bandwidth (≤ −20 dB) of the composite material covers 3 ∼ 16 GHz when the coating thickness is from 1.5 to 5.0 mm. The minimum value of the reflection loss (RLmin) reaches − 71.5 dB when the frequency is 5.68 GHz, and the coating thickness is 3.85 mm. The research scheme of pre-oxidation and then composite with MOFs materials not only realizes the controllable preparation of high-performance FeSiAl composites, but also enhances the stability and corrosion resistance of the material. This work provides a new way to realize in situ composite of high permeability alloy materials and MOFs materials.