Dependence of the effective permeability on annealing and the annealing-induced structural change for amorphous Fe_(73.5)Cu₁M₃Si_(13.5)B_9(M=V, Nb, Mo, Ta or W)and Fe_(73.5)Cu₁Nb₃(Si_xB_(1-x))_(22.5)(x=0∼0.8) alloys were investigated. Crystalline Fe_(73.5)Cu₁M₃Si_(13.5)B_9(M=V, Nb, Mo, W)alloys with α-Fe phase which was obtained by annealing at above T_x showed higher effective permeability than with amorphous phase, and the increase in permeability upon crystallization was large in the order of V$lt;W$lt;Mo$lt;Nb. For amorphous Fe_(73.5)Cu₁Nb₃(Si_xB_(1-x))_(22.5) alloys in the composition range from x=0.5 to 0.8, soft magnetic property was improved by crystallization. Moreover, in that composition range, the effective permeability increased with the Si content(x). Superior soft magnetic property of the high-Si alloys was attributed to both the small magnetocrystalline anisotropy and the low magnetostriction. The effective permeabilities measured at 1㎑ and 5 m0e for crystalline Fe-Cu-Mo-Si-B and Fe-Cu-Nb-Si-B(0.5≤x≤0.8) alloys were about 1∼2 × 10⁴, and it was comparable to that of the zero-magnetostriction Co-based amorphous alloys. |
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