Effect of chemically active medium on frequency dependence of magnetic losses in soft magnetic Fe-based amorphous alloys

The effects of the electrolytic hydrogenation and oxidation and of the interaction of the surface ribbon with water and vapor on the frequency dependence of magnetic losses per magnetization-reversal cycle are studied based on the example of soft magnetic Fe81B13Si 4C2 amorphous alloy, which exhibits a positive saturation magnetostriction. It was shown that, after the hydrogenation and oxidation of soft magnetic amorphous alloys, their frequency dependences of magnetic losses per magnetization-reversal cycle, which are reduced to unit induction, exhibit groups of hydrogen- and oxygen-related peaks in the frequency ranges of 35-55 and 55-80 Hz, which can be explained by the formation of O-A and H-A atomic pairs (where A are atoms of alloy components) and their reorientation in a magnetic field in the course of magnetization reversal at certain frequencies. The formation of analogous groups of peaks for samples of soft magnetic Fe-based amorphous alloys was observed after the interaction of the ribbon surface with water and vapor and after heat treatment in air. This fact confirms the possibility of the hydrogenation and oxidation of the alloys during the aforementioned processes. © 2013 Pleiades Publishing, Ltd

Effect of parameters of heat treatment on magnetic properties and magnetization distribution in ribbons of amorphous soft magnetic iron-based alloys

The effect of the isothermal-holding temperature and cooling rate upon in-air heat treatment on the magnetic properties and magnetization distribution in ribbons of amorphous soft magnetic iron-based alloys with positive saturation magnetostriction has been investigated. The results of the investigation showed that the dependence of the maximum magnetic permeability on the isothermal-holding temperature correlates with the corresponding changes in the magnetization distribution in the ribbon and is determined by diffusion processes that occur upon in-air heat treatment at a specific isothermal-holding temperature. An increase in the cooling rate leads to an ambiguous effect on the level of magnetic properties. The increase favors an improvement in magnetic properties when, after in-air heat treatment, either a predominantly amorphous state of the surface or a state with the formed amorphous-crystalline surface layer with a nearly optimal thickness is obtained. © 2013 Pleiades Publishing, Ltd

INHOMOGENEITY OF THE MAGNETIC CHARACTERISTICS OF AN AMORPHOUS COBALT-BASED ALLOY IN THE AS-QUENCHED STATE

The studies shown the presence of inhomogeneity in the magnetic characteristics of co-balt-based amorphous soft magnetic alloy AMAG-172 in the as-quenched state. The inhomo-geneity of the characteristics can be associated with inhomogeneous cooling of the ribbon during the manufacture

Mechanisms of the Magnetic Properties Improvement of Amorphous Soft Magnetic Fe- and Co-based Alloys as a Result of the in-air Heat Treatment

Physical causes of the formation of magnetic characteristics amorphous soft magnetic alloys under heat treatment in air have been studied. It has been established that the physical causes of the formation of the magnetic characteristics of the cobalt-based alloys are the same as those for iron-based alloys. Change in the magnetic characteristics after annealing results from the relaxation of the quenching induced internal stresses, as well as from the effect of the stresses induced by the hydrogen and oxygen atoms embedded into the ribbon surface in the course of its interaction with water vapor in air and by the formation of the amorphous-crystalline surface layer. The study of the magnetization distribution and the magnetic characteristics of the Co-Fe-Ni-Cr-Si-B amorphous soft magnetic alloy have shown the possibility of using the vapor treatment of the amorphous soft magnetic alloy ribbon surface to determine the sign of its magnetostriction. The magnetostriction sign dependence on the structural state of the ribbon is found on the basis of the obtained results. © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.This work was supported in part by the Ministry of Education and Science of Russian Federation, unique identifier of applied research and experimental developments RFMEFI62514X0018