Improvement of core loss by chemical thinning in a thick amorphous alloy ribbon

The effects of chemical thinning after annealing were examined on amorphous Fe-base alloy ribbons with different thicknesses (25 and 60 μm) to further improve their core loss. The core loss of a 60-μm-thick ribbon decreased with thickness reduction and reached a minimum (0.04 W/kg at 50 Hz and 1.3 T) at 10 μm. On the other hand, for a 25-μm-thick ribbon treated in the same manner, the minimum core loss was as large as 0.09 W/kg. The very low core loss of a thick ribbon results from low hysteresis loss, which remains constant over a wide thickness range during thinning. The low hysteresis loss of a thick amorphous ribbon is possibly due to its high structural homogeneity