A microwave study of intrinsic permeability of mechanically activatedpowders of Fe-based alloys

摘要

The structure and microwave magnetic performance of Fe, Fe-Si-C, and Fe-Co-Si-Cpowders fabricated by mechanical milling has been studied. The study was aimed at revealing of theeffect of shape, composition, and structure of the powder particles on the microwave frequencydispersion of permeability of the powder-filled composites in the frequency range of 0.1-3 GHz. Atlow frequencies, below 1 GHz, the main reason causing the differences in the microwave magneticproperties of the powders is the shape of powder particles. At higher frequencies, the magneticperformance is mainly due to the effect of eddy currents and is determined by the size of powderparticles. The difference in the composition of the powders under study and, therefore,corresponding differences in intrinsic permeability of these have a minor effect on the microwavemagnetic performance as compared to the effects of particle size and shape.