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

Abstract

Abstract-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 corre lates with the corresponding changes in the magnetization distribution in the ribbon and is determined by dif fusion 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.

Effects of air annealing on Fe–Si–B–M–Cu (M=Nb, Mo) alloys

“…Since the alloys have positive magnetostriction (2.2 and 2.7 for Nb and Mo vacuum-annealed alloys, respectively [10]), the easy axis of the ribbons tilts off the long axis. This same effect of air heat treatment on the magnetic properties of iron-based alloys with positive saturation magnetostriction was also observed by Skulkina et al [22].…”

Crystallization kinetics and soft magnetic properties of Fe71Si16B9Cu1Nb3 amorphous alloys

“…It can be seen that when the annealing temperature increased from T x1 -30 K(761 K) to T end +5 K(858 K), the magnetic properties of the amorphous ribbon increased with an increase in the annealing temperature, and the saturation magnetic induction B s increased from 1.19 T to 1.35 T. Since 761 K, 786 K, and 801 K are in the supercooled liquid phase of the amorphous ribbon to the initial stage of the crystallization process, nucleation is difficult at this stage. As such, the annealing process does not have much influence on the crystallization process; it mainly serves to remove residual stress [27]. The coercive forces of the amorphous ribbon after annealing at 761 K, 786 K, and 801 K for 300 s were reduced compared to that of the original amorphous ribbon.…”

Magnetic Properties of Rapidly Quenched Ribbons of Soft Magnetic Iron-Based Alloys after Annealing in Air and in Vacuum

“…A thermal treatment that is carried out in different environments (e.g. annealing in vacuum, inert gas, air), is standard methods of improving of magnetic properties, as a rule, due to a decrease of quenching-induced internal stresses [1,3,4]. Combined with the heat treatment applied thermomagnetic and laser treatments to improve the magnetic properties.…”

“…It should not lead to noticeable oxidation of a surface of a ribbon because of the relatively low temperature of isothermal shutter speed (350 -400 o C). Along with the stress relaxation, the reaction between the ribbon surface and water vapor present in air and the formation of surface amorphous-crystalline layer are of importance [4]. The physical cause of the influence of a thermal treatment in the air and in the vacuum on the magnetic properties of amorphous soft magnetic iron-based alloys was investigated in this work to optimize the magnetic properties.…”