Engineering magnetic properties of Fe-Ni-B amorphous alloys

Amorphous alloys in the series (FexNi1-x)80B20were prepared by melt spinning with 20 < x < 80<. Losses and permeabilities are reported for frequencies from 100 Hz to 100 kHz. The as-wound toroids showed an increase in losses and a decrease in permeability with increasing x, consistent with the increase in magnetostriction observed with increasing x. After stress relief annealing of the toroids, maximum losses were observed at x = 75. This composition corresponds to the composition at which the magnetic anneal anisotropy is maximum.