A study of the crystallization behavior of an amorphous Fe 77.5Si 13.5B 9 alloy

Abstract

The crystallization behavior of an amorphous Fe 77.5Si 13.5B 9 alloy was studied by means of DSC, XRD, TEM, EDX and VSM techniques. Crystallization induced by heat treatment resulted in the formation of a Fe–Si phase with an unusual morphology: the branches of the dendrite were composed of closely spaced crystals, the spacing of such crystals was of the order of nanometer. Due to this dendritic morphology, the products of secondary crystallization grew not only among the dendritic branches but also within the dendrites at the interfaces of the closely spaced crystals. The products of secondary crystallization have a striped morphology and consist of the Fe–Si phase with B2 ordered structure and the Fe 3B phase. The final products of crystallization were the striped structure composed of the Fe–Si, Fe 2B and the Fe 3B phases. The Fe–Si phase was also found in the form of large crystals. The magnetization values showed little change as annealing time and temperatures were increased while the coercivity increased significantly due to the formation of the Fe 3B and Fe 2B phase.