The non-isothermal crystallization kinetics and mechanism of FeGaGeBCu alloy

In this paper, Fe76Ga5Ge5B13Cu1 ribbon was prepared by melt spinning method and its thermal stability and non-isothermal crystallization kinetics were analyzed. It is found that the primary crystallization phase is alpha-Fe(Ga, Ge), following by the precipitation of Fe-B compounds. Besides, Kissinger and Ozawa methods were utilized to calculate the initial activation energy E-x and apparent activation energy E-a. The results show that E-x1 > E-a1, which is due to that the diffusion of Ga and Ge is difficult during the nucleation process but left a channel for the subsequent diffusion of atoms. In addition, Avrami index n was calculated by Johnson-Mehl-Avrami-Kolmogorov (JMAK) model and the crystallization mechanism of Fe76Ga5Ge5B13Cu1 alloy was analyzed. For the alloy with grains or clusters embedded in the amorphous matrix, it is concluded that the annealing condition with a higher heating rate is more conducive to obtain homogeneous nanocrystalline and improve soft magnetic properties.