Designing the composition and heat treatment of magnetic amorphous alloys

Abstract

The amorphous alloys obtained by rapid quenching are considered to have excellent potential for industrial application. In selecting an alloy for a specific application, however, considerations in many areas are required. The properties of the amorphous alloys depend not only on the chemical composition but also on the quenching condition and the post-quenching heat treatment. The response of the alloy to heat treatments again depends on the composition. Furthermore, often a combination of various properties is required for a particular application, and it is not necessarily easy to find a single alloy which satisfies all the requirements simultaneously. In this paper we review some of the important factors which have to be considered in designing the alloy primarily for magnetic applications. It is not intended to provide a comprehensive review of all properties or effects, but an attempt is made to illustrate the limitations and opportunities in designing alloys for magnetic transition metal-metalloid amorphous alloys. The subjects covered include the composition dependence of the bulk physical and chemical properties of the amorphous alloys, the effects of heat treatment on the structure-sensitive properties, the combined effects of composition and heat treatment which have seldom been discussed explicitly in the literature and the examples of the alloy design for some applications.