Interaction of the surfaces of ribbons of amorphous magnetically soft alloys with vapor at various stages of heat treatment

Abstract

The effect of heat treatment in air atmosphere combined with water vapor on the distribution of magnetization and on magnetic characteristics has been studied based on the example of a rapidly quenched amorphous magnetically soft Fe77Ni1Si9B13 alloy, which possesses a positive saturation magnetostriction. The interaction of the surface of a ribbon made of the alloy with vapor was implemented at various stages of heat treatment, such as heating, cooling, and isothermal holding. The results of the study have confirmed an important contribution of the stresses induced by hydrogen and oxygen atoms, which are incorporated into the surface of the ribbon, to the formation of the magnetic characteristics of the alloy. The heat treatment of the surface of the ribbon with vapor at various stages together with varying rate of cooling substantially enhance the maximum magnetic permeability at an optimum duration of isothermal holding. This is primarily due to a decrease in the relative volume of orthogonal-magnetization domains because of an additional rise in predominantly plane tensile stresses induced by hydrogen and oxygen atoms which are incorporated into the surface of the ribbon.