1999 Volume 63 Issue 2 Pages 237-242
We investigated the frequency characteristics of permeability for an Fe-Si-Al flakes/polymer composite which has dual frequency dispersion in permeability. From the relation of Curie temperature to the powder surface area, it was found that the mother alloy composition changes with progress of attrition to excess Fe, and as a result, magneto-elastic effect seems to give a large influence on the permeability. Moreover, the results of XPS analysis for bulk samples and compositional dependence of Curie temperature suggests that oxidation of Si and Al at the powder surface leads to excess Fe in the total composition of the powder. Based on these findings, a raw material was prepared adjusting the amount of Fe. Consequently, the Fe-Si-Al flakes/polymer composite exhibits excellent EMI suppressing characteristics in a quasi-microwave band.
