MFe2O4 (M=Mn, co, Ni, Zn) ferrite nanosheets coated flaky FeSiAl composite powder and their magnetism and microwave absorption

Magnetite (MFe2O4, M = Mn, Zn, Ni, Co) nanosheet coated flaky FeSiAl alloy composite powder have been successfully synthesized. The morphology, composition, crystal structures, magnetism and electromagnetic performance of composite powder were studied systematically. Spinel ferrite nanosheet were prepared on the surface of flaky FeSiAl by hydroxide deposition decomposition. This structure will benefit the microwave multiple reflection loss. The saturation magnetization of the composite powder decreased with ferrite coating. The ZnFe2O4 coated composite exhibited higher saturation magnetization while the CoFe2O4 coated composite had the highest coercivity. Owing to the oxide coating, the complex permittivity and dielectric loss of the composite powder were evidently increased while the magnetic loss significantly decreased. Magnetic loss was dominant under 13 GHz and dielectric loss contributed equally as magnetic loss at higher frequency. Therefore, the composite powder attenuate the electromagnetic waves much more efficiently at higher frequency. Our results provide a reference to understand the effect of ferrite nanosheet coating on the magnetism and design the microwave absorption of composite powder materials.