Abstract
Magnetic properties of Fe-Cu-M-Si-B (M: Nb, Mo, Ta, W, etc.) alloys prepared by annealing amorphous alloys were investigated for development of new Fe based soft magnetic alloys. In the case of annealing the alloys above the crystallization temperature, excellent soft magnebc properties which correspond to those of Co based amorphous alloys were obtained. Especially, the alloys containing Cu and Nb were superior to the alloys containing other elements.
These new alloys were composed of ultrafine grain structure. The alloys were about 10 nm in grain diameter and the main phase of them was presumed to be a bcc Fe solid solution which contains Si and B. This might be attributed to the effect of the bcc Fe solid solution nucleation by Cu and the suppression of the grain growth by Nb.
The newly developed alloys are suitable for many kinds of magnetic components such as saturable reactors, choke coiles and transformers because of their excellent soft magnetic properties and high saturation flux density.
