Magnetic softening and hardening in Metglas (R) 2605SC at the onset of nanocrystallization

Abstract

Mossbauer spectroscopy, coercive field and permeability were used to study the transformations produced by annealing at 375 degrees C as-quenched amorphous ribbons of Metglas(R) 2605 SC of nominal composition Fe81B13.5Si3.5C2. The coercive field showed a decrease (softening) in the 0-30 min range, followed by an increase (hardening) for annealing times above 30 min. Permeability exhibited the opposite behavior, with a maximum for about 30 min. The Mossbauer magnetic hyperfine spectra showed variations in the intensities ratios, which were related with macroscopic measurements in good agreement with the softening-hardening processes.