Thermal effect on structural and magnetic properties of Fe₇₈B₁₃Si₉ annealed amorphous ribbons

¹ LPS, Dpt. de Physique-Annaba University, Route d’El Hadjar BP 12 Annaba, Algérie
² GMS-LPCS UMR 7045, Chimie Paristech, 11 rue Pierre et Marie Curie, F-75231 Paris Cedex 05, France
³ LCP –A2MC Institut de Chimie, Physique et Matériaux, Université de Lorraine, 1 bd Dominique François Arago 57078, Metz Cedex 3, France

^* Corresponding author: ml_soltani@yahoo.com

Published online: 21 August 2017

Abstract

In the present work, we study the influence of thermal treatments on the magnetic properties of as-quenched and pre-crystallized Fe₇₈Si₉B₁₃ after stress relaxation. The crystallization behavior of amorphous and treated Fe₇₈Si₉B₁₃ ribbons was revisited. The measurements were carried out by means of Differential Scanning Calorimetry, by X-ray diffraction and by Vibrating Sample Magnetometer, Susceptometer and fluxmeter. Relaxed samples were heated in the resistivity device up to 700°C and annealed near the onset temperature about 420°C for respectively 1, 3, 5, 8 hours. In as-quenched samples, two transition points occur at about 505°C and 564°C but in relaxed sample, the transition points have been found about 552°C and 568°C. Kinetics of crystallization was deduced for all studied samples. Annealing of the as-purchased ribbon shows the occurrence of α-Fe and tetragonal Fe₃B resulting from the crystallization of the remaining amorphous phase. The effects on magnetic properties were pointed out by relating the structural evolution of the samples. The magnetic measurements show that annealing change the saturation magnetization and the coercive magnetic field values, hence destroying the good magnetic properties of the material. The heat treatment shows that the crystallization has greatly altered the shape of the cycles and moved the magnetic saturation point of the samples. The effect of treatment on the magneto-crystalline anisotropy is also demonstrated.