Influence of a Protective Coating on the Crystallization of an Amorphous Fe78Si13B9 Alloy

The effect of free volume on the crystallization of amorphous Fe78Si13B9 ribbons was studied using ultrasonic and thermal treatments. To maintain free volume under heating, amorphous samples were coated with a special protective Ta coating. It has been shown via X-ray diffraction that the fraction of the crystalline phase in the annealed coated amorphous ribbons is higher than in the corresponding uncoated samples. The use of ultrasonic treatment and the application of a protective coating lead to the formation of a larger proportion of the crystalline phase during annealing. Differences in crystallization kinetics are discussed under the assumption that the concentration of free volume in amorphous samples affects their crystallization, as well as the role of the Ta coating preventing the release of free volume to the surface during heat treatment.