Effect of Fe content on crystallization behaviors and magnetic properties of amorphous alloys Fe_x(SiB)_96-xP₃Cu₁

Crystallization behavior and soft magnetic properties of amorphous alloys Fe_x(SiB)_96-xP₃Cu₁ (x=75, 78, 80, 83 and 85, atomic fraction, %) were investigated. It was found that the apparent activation energy for crystallization decreased with the increasing Fe content of the Fe_x(SiB)_96-xP₃Cu₁ alloys. The phases precipitated after properly complete crystallization treatment were the same for all the alloys with varying Fe content. The annealed Fe_x(SiB)_96-xP₃Cu₁ (x=80, 83 and 85) alloys exhibited a uniform nanostructure with grain size smaller than 20 nm, while the grain sizes of the alloys with x=75 and 78 ranged from 5 nm to 50 nm. The saturation magnetization enhanced nonlinearly as the Fe content increased from 75 to 85. The nanocrystalline alloy Fe₈₅Si₃B₈P₃Cu₁ exhibited excellent soft magnetic properties with a coercivity of 12 A·m^-1 and a saturation magnetization of 1.87 T. The core loss values of nanocrystalline alloys Fe₈₅Si₃B₈P₃Cu₁ and Fe₈₃Si₄B₉P₃Cu₁ were still less than 1.0 W·kg^-1 even if the saturation magnetic induction intensity was up to 1.7 T, which were superior to that of the commercial Fe₇₈Si₉B₁₃ alloy and nonorientated silicon steel.