A STUDY OF FLASH-ANNEALED FEMNSIB AMORPHOUS CORES

The effect of flash annealing on the properties of Fe-based alloys was studied in some detail and compared with the properties resulting fro m conventional furnace annealing. It was found that flash annealing is an efficient way to obtain low H(c) for amorphous alloys. The optimum H(c) values obtained by this method is as low as 0.034 Oe and 0.028 O e for alloys 4 (Fe74.5Mn3.5Si12B10) and 8* (Fe75Mn6Si8B11) respective ly, which are comparable with those of conventional methods. Stress re lief test and electron diffraction results confirmed that the stress r elief process plays an important role in reducing H(c) instead of the appearance of nanocrystallinity. It became clear through experiment th at the local temperature in ribbons during flash annealing varies from place to place, introducing to die ribbon a non-uniform structure, wh ich results in non-sinusoidal, non-uniform and non-repetitive domain w all motion and, as a consequence, higher anomalous losses at high freq uency ranges.