Crystallization Phases and Crystallization Saturation Magnetization Under Different Annealing Ways in Fe-Rich Fe-B/SiBP-Cu-Hf Alloys

摘要

Entirely amorphous ribbons are successfully fabricated by adding Hf for half Cu in Fe-rich Fe₈₆B₁₃Cu_1-xHf_xand Fe₈₅Si₂B₈P₄Cu_1-yHf_yalloys, which indicates that Hf plays a positive role in promoting the glass forming ability. Differential scanning calorimetry curves of both Fe₈₆B₁₃Cu_0.5Hf_0.5and Fe₈₅Si₂B₈P₄Cu_0.5Hf_0.5amorphous ribbons show two obvious exothermic peaks, which implies the alloys will need a two-step crystallization before reaching the stable state in the subsequent crystallization process. During the normal annealing, α-Fe grains are formed initially at 623 K, later the Fe₈₅Si₂B₈P₄Cu_0.5Hf_0.5alloy starts to form Fe-(B, P) compounds at 723 K, while the Fe₈₆B₁₃Cu_0.5Hf_0.5alloy only begins to precipitate Fe-B compounds at a relatively higher temperature of 798 K. However, for flashing annealing, both the amorphous ribbons only start the initial crystallization of α-Fe phase as the annealing temperature less than T_x2(the onset temperature of the secondary crystallization). Ms (saturation magnetization) values of both Fe₈₆B₁₃Cu_0.5Hf_0.5and Fe₈₅Si₂B₈P₄Cu_0.5Hf_0.5ribbons show an increasing trend after annealing and reach a maximum of about 206.3 and 212.2 emu/g by normal annealing and 208.2 and 216.2 emu/g by flashing annealing, respectively. Therefore, crystallization phases and Ms are easier and more effective to be adjusted by flash annealing, and further, the ribbons with uniform α-Fe phase show excellent soft magnetic properties.