A study of electromagnetic characteristics of Fe-Si-Al magnetic alloy

Fe-Si-Al magnetic alloy powders, consisting of Si 9.7wt%-Al 5.4wt%-bal Fe, were prepared by mechanical alloying. The appearance, phase composition, complex permeability μ˙, complex permittivity ε˙ of different milling time samples were measured respectively by SEM, X-ray diffraction and microwave vector network analysis in the 2-18 GHz band. Variations of the electromagnetic characteristics in the mechanical alloying process were analyzed. The aspect ratio of samples increased with the milling time, and the aspect ratio about 50-60 of the 300 h milling sample was observed by SEM. The X-ray diffraction peak of the 300 h milling sample was the most screechy, and the values of μ\´ and μ" were over 3.7 and 2.0 respectively. The frequency dependence of reflection loss of the 300 h milling samples with different thickness was measured by the Agilent 8722ES microwave vector network analyzer. Result showed that the electromagnetic characteristics of the materials can be controlled by the variation of the mechanical alloying process. These novel materials can be used in EMC systems.