THE EFFECT OF COMPOSITION ON THE CRYSTALLIZATION AND MAGNETIC TRANSITION OF FE-SI-B AMORPHOUS-ALLOYS

This paper presents the effect of the metalloid composition on the cry stallization and the magnetic phase transition of Fe-Si-B amorphous al loys. The phenomenon of two exothermic peaks (MS-I and MS-II phases) c orrelated with the crystallization behavior was examined by means of d ifferential scanning calorimetry (DSC). The magnetic phase transition process was investigated by thermogravimetric analysis under a magneti c field (M-TGA). The microstructural evolution was studied by means of transmission electron microscopy (TEM). For the lower metalloid conte nts, the MS-I and MS-II phases were revealed to be a crystalline alpha -Fe structure and a compound structure with a large amount of metalloi d elements, while for the higher metalloid contents,the compound of me talloid elements may be observed only in the MS-I phase. The precipita tion temperature of the alpha-Fe phase exhibits a decreasing trend wit h increasing iron content. The Curie transition temperature of Fe-Si-B amorphous alloys also decreases with increasing iron content. The pha se transitions of the DSC measurements were in good agreement with tho se measured by TGA under a magnetic field.