Magnetic properties of FeCu (3d transition metals) SiB alloys with fine grain structure

Soft magnetic properties were investigated together with crystallization process and grain size for FeCu (3d transition metals) SiB alloys with fine grains. They were rapidly quenched from the melt to achieve amorphous states and then annealed above their crystallization temperatures. In the group of 3d transition metals studied, low magnetic core loss at high frequency was obtained for V‐substituted Fe‐based alloys, because only a bcc Fe solid solution with diameter of about 20 nm precipitated. On the other hand, Cr‐ or Mn‐substituted alloys could not be attained with good soft magnetic properties because of the existence of Fe‐metalloid compounds besides the bcc phase by annealing above their crystallization temperatures. The effect of grain size on the soft magnetic properties is more prominent at lower frequency. Diffraction peaks which are characteristics of an ordered phase (DO3) are observed, which is the origin of excellent soft magnetic properties in FeAlSi alloys.