Abstract
Soft magnetic composite materials consisting of FeSi powder and polypropylene were prepared by the injection molding method, with different polypropylene contents of 25, 30 and 35 vol. %. The magnetic and electrical properties as well as the structure of the composites were investigated. The samples exhibited very low porosity, high electrical resistivity, relatively low coercivity, sufficient saturation magnetic flux density and permeability, and high resonant frequency. FeSi particles were found to be well insulated from each other and homogeneously dispersed in the polymer matrix of the composite. The observed isotropic structure was confirmed by the fitting of the experimental dependence with the analytical expression of the reversible relative permeability vs. magnetic flux density.