Nanocrystallization Behavior and Soft Magnetic Properties of FeSiBCu(C) Amorphous Alloy

Developing Fe-based nanocrystalline alloys with high saturation flux density (Bs) is essential for a wide range of technologies. In present work, effects of minor C addition as well as stress-relaxation treatment on nanocrystallization and magnetic properties of Fe-based amorphous alloys were systematically studied. For this reason, Fe۸۳.۳Si۴B۱۲Cu۰.۷ and Fe۸۲.۳Si۴B۱۲Cu۰.۷C۱ amorphous ribbons were produced by melt spinning process and were subjected to heat treatment at a temperature of ۶۴۰ K for ۱ hour. The crystallization temperatures were derived by DSC technique. Structural investigations performed at room temperature X-ray diffractometry confirmed amorphous nature of the as-spun ribbons and the presence of α-Fe nanocrystalline phases embedded in amorphous matrix in annealed ones. Using VSM technique, it has been found that although the addition of C decreases the value of Bs somewhat, the C-containing alloy still shows good magnetic properties, including relatively high Bs (۱۳۳ emu/g) and low coercivity (۰.۳ G). The saturation magnetization of relaxed annealed samples increased significantly (۱۵۳ emu/g and ۱۸۴.۵ emu/g for C-free and C-containing alloys, respectively) while Hc had a tendency to decrease. Improved soft magnetic properties after annealing could be attributed to the α-Fe nanocrystalline phases which were separated out, in addition to chemical rearrangement of atoms and annihilation of free-volume.

Keywords:

Nanomaterials , Amorphous , nanocrystallization , magnetic properties , heat treatment