Nanocrystalline Particles In Fesib Preparation And Microwave Electromagnetic Characteristics

For high saturation magnetization, low coercive force and low magnetic anisotropy due to nanocrystalline structure, FeSiB nanocrystalline particles are promising to achieve high microwave permeability. In this paper we analysed the structure of phase and morphology of FeSiB nanocrystalline particles produced by Mechanical Alloying (MA), and studied their static,dynemic electromagnetic properties from the aspects of composition,grain size and particle size etc. As the results of experiments: Under the condition of experiment in this paper, the alloying product is nanostructred α?Fe(Si) solid solution when Si% ≤40at%,which was beyond the limit( Si % ≤25at%) in phase diagram. While Si% > 40at%,the MA products of Fe40Si60 were the mixture of Si,α?Fe(Si),FeSi,β?FeSi2. For low solubility in α-Fe, the introduction of B was helpful to form amorphous phase located in the boundary among crystalline grain. The complex structure of the nanocrystalline phase α?Fe(Si)/ amorphous phase was formed. With the particle size of FeSiB nanocrystalline particles being decreased the complex permeability and permittivity were increased synchronously. When Si was introduced in the nanocrystalline phase α?Fe(Si) was formed , which was helpful to decrease magnetic anisotropy then to increase the complex permeability. The change of B% resulted in the amount of amorphous phase , which would affect the complex permeability and permittivity. In this paper we calculated and simulated the absorption properties of FeSiB nanocrystalline particles and found that the absorption properties of FeSiB nanocrystalline particles were affected observably by composition,nanocrystalline structure and particle size. The simulation was testified correct by the results of experiments.