Amorphous to nanocrystalline transformation in Fe77.5Cu1Nb3Si9.5B9 alloy

Nanocrystalline magnetic phases obtained by suitably annealing amorphous metallic ribbons are being extensively studied due to their attractive properties as soft magnetic materials. The amorphous-to-nanocrystalline transformation of a Fe77.5Cu1Nb3Si9.5B9 alloy was monitored by thermal, structural, and thermomagnetic measurements. Calorimetric results obtained in continuous heating regime reveal that several exothermic events appear during the whole crystallization process and the presence of a peak at the amorphous Curie temperature of about 560 K. In addition, thermomagnetic measurements show the Curie temperatures of the amorphous, nanocrystalline structure as well as those corresponding to the different magnetic phases that appear during crystallization. The apparent activation energy for the nanocrystalline transformation has a value of 332 kJ/at.g. The crystallized phases were identified by X-ray diffraction. Particular attention has been paid to how the properties of nanostructured sample changes with thermal treatment carried out on glassy precursors.