New Fe–Co–Ni–Zr–B Amorphous Alloys with Wide Supercooled Liquid Regions and Good Soft Magnetic Properties

Abstract

New Fe-based amorphous alloys in Fe-Co-Ni-Zr-B system exhibiting a wide supercooled liquid region before crystallization and good soft magnetic properties were found to be formed by melt spinning. The composition range of the amorphous (Fe 1-x-y Co x Ni y ) 70 Zr 10 B 20 alloys with the wide supercooled liquid region above 50 K extends from 0 to 36 at%Co and 0 to 30%Ni and the largest value of the supercooled liquid region defined by the difference between the glass transition temperature (T g ) and crystallization temperature (T x ), ΔT x ( = T x - T g ) is 68 K for Fe 56 Co 7 Ni 7 Zr 10 B 20 . The crystallization from the supercooled liquid of the Fe 56 Co 7 Ni 7 Zr 10 B 20 alloy upon continuous heating occurs through a single stage and the resulting crystallized structure consists of α-Fe, Fe2Zr and Fe 3 B phases containing Co and Ni elements. These Fe-based amorphous alloys exhibit good soft magnetic properties and the saturation magnetization, coercive force, permeability at I kHz and Curie temperature are respectively 0.96 T, 2.41 A/m, 17700 and 567 K for the amorphous Fe 56 Co 7 Ni 7 Zr 10 B 20 alloy annealed for 600 s at 750 K. The finding of the Fe-based amorphous alloys with good soft magnetic properties and high thermal stability of the supercooled liquid is important for future development of ferromagnetic bulk amorphous alloys.