Investigation Of Microwave Absorbing Capability Of Fe-based Nano-crystalline Alloy Flakes

The nanocrystalline magnetic alloy has excellent soft magnetic properties and high frequency electromagnetic characteristics and they have already being applied extensively in electronic information industry. Flaky morphology of magnetic alloy particle material can raise its natural resonance frequency because of strong shape anisotropy, which is advantageous to acquiring high microwave permeability .According to this, magnetic alloy flakes with nanocrystalline structure were adopted to manufacture microwave absorber with high permeability and magnetism loss near 2 GHz. Thus, it is possible to design and prepare thin layer absorber material with broad bandwidth and strong absorption.Firstly, domestic and international development of microwave absorber was described. And then, the problems of microwave absorber development in our country were discussed. Magnetic alloy flakes with nanocrystalline structure were chosen to solve the problem of bad absorbing performance near 2 GHz. Then, the physical mechanism of high permeability of the nanocrystalline structure soft magnetism alloy materials, the relationship between resistance of nanocrystalline alloy materials and nanocrystalline structure, and the magnetic connotation of alloy flakes with particular shape anisotropy having high microwave permeability were presented. The experimental details and related analysis measurement techniques were also introduced in the paper. The influence of melt-quenching, high energy ball milling treatment and vacuum heat treatment upon microstructure, microwave electromagnetic characteristics and microwave absorption properties of the nanocrystalline FeSiAl flakes was investigated. Results of electromagnetic characteristics, microstructure and morphology were discussed in detail. The nanocrystalline FeSiAl flakes of high permeability and large magnetism loss near 2 GHz were prepared. And the result of simulation and practical measurement of microwave absorbing coat of the nanocrystalline FeSiAl flakes prove that the microwave absorption properties of such FeSiAl flakes near 2 GHz. are excellent. Thus, the nanocrystalline FeSiAl flakes can be applied for designing and preparing microwave absorber operating in broad bandwidth.