采用单辊旋淬法制备了Fe₇₆Ga₅Ge₅B₆P₇Cu₁带材,并研究了其晶化行为和机理。结果表明Fe₇₆Ga₅Ge₅B₆-P₇Cu₁合金的晶化过程分为2个阶段,第1个阶段为α-Fe(Ga, Ge)相的析出,第2个阶段为Fe(B, P)硬磁相的析出。在非等温加热的情况下,初始表观激活能大于晶化表观激活能。根据Johnson-Mehl-Avrami-Kolmogorov (JMAK)方程得出,对于非完全非晶结构的合金,其晶化过程为预先存在的晶核或团簇不断长大,同时伴随着新的晶核不断析出且形核率不断下降。此外,快速升温的退火工艺更适合形成均匀弥散的纳米晶组织。通过实验验证,退火时升温速率为100 K/min的合金软磁性能优于升温速率为10和50 K/min的合金,其最优起始磁导率为2.86 × 10^-2 H/m,矫顽力为1.77 A/m。

Fe-based amorphous and nanocrystalline alloys can be used for technological applications on iron core materials owing to their high permeability, low coercivity, and core loss. However, when compared to Si-steels, their application is limited owing to low saturation magnetization. Thus, the saturation magnetization of Fe-based amorphous and nanocrystalline alloys should be improved, which may reduce the content of metalloid elements, and thus, the amorphous forming ability. Consequently, as-spun Fe-based amorphous and nanocrystalline alloys with high saturation magnetization may be incompletely amorphous. In this case, annealing processes should be modified by investigating crystallization behavior because traditional annealing processes with low heating rates may degrade ferromagnetic exchange and soft magnetic properties owing to grain-size inhomogeneity. Fe₇₆Ga₅Ge₅B₆P₇Cu₁ ribbons were fabricated using the melt spinning technique, and their crystallization behavior and mechanism were studied. Results showed that two exothermic peaks are present in the DSC curve, which correspond to the precipitation of α-Fe(Ga, Ge) and Fe(B, P) phases. Under nonisothermal conditions, the initial activation energy is greater than the apparent activation energy. According to the Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation, for an incomplete amorphous alloy, the crystallization process combines the growth of pre-existing nucleus and nucleation, whereas the nucleation rate decreases. Moreover, a rapid heating annealing process is conducive to the formation of a uniform and dispersed nanocrystalline structure. It was found that the magnetic properties of the annealed alloy with a heating rate of 100 K/min was better than those with 10 and 50 K/min. Further, the optimal initial permeability was 2.86 × 10^-2 H/m, and the coercivity was 1.77 A/m.