IMPACT OF ANNEALING TIME ON THE FORMATION OF NANOCRYSTAL IN AMORPHOUS FE75.5SI13.5CU1NB1B9 ALLOY AND THEIR ULTRA-SOFT MAGNETIC PROPERTIES.

To observe the impact of the annealing time on the alloy structure and ultra-soft magnetic properties of Fe_75.5Si_13.5Cu₁Nb₁B₉, the alloy was annealed in a controlled way in the temperature range 475 - 600°C for different annealing time from 5 to 30 min. Amorphosity of the ribbon and nanocrystalline state was evaluated by X-ray diffraction. Grain size and Si content increase with increasing annealing temperature and time; on the other hand lattice parameter decrease with increasing annealing temperature and time. The maximum permeability was observed at annealing temperature Ta = 525°C for 15 min, and thereafter it starts to decreases. Saturation magnetization increases with annealing temperature Ta for the samples and finally decreases during annealing at a temperature much higher than peak crystallization temperature. The results of the experimental observations are explained on the basis of existing theories of nanocrystalline amorphous metallic ribbons. [ABSTRACT FROM AUTHOR]