NEW FE-CO-NI-ZR-B AMORPHOUS-ALLOYS WITH WIDE SUPERCOOLED LIQUID REGIONS AND GOOD SOFT-MAGNETIC PROPERTIES

New Fe-based amorphous alloys in Fe-Co-Ni-Zr-B system exhibiting a wid e supercooled liquid region before crystallization and good soft magne tic properties were found to be formed by melt spinning. The compositi on range of the amorphous (Fe1-x-yCoxNiy)(70)Zr10B20 alloys with the w ide supercooled liquid region above 50 K extends from 0 to 36 at%Co an d 0 to 30%Ni and the largest value of the supercooled liquid region de fined by the difference between the glass transition temperature (T-g) and crystallization temperature (T-x), Delta T-x(= T-x - T-g) is 68 K for Fe56Co7Ni7Zr10B20. The crystallization from the supercooled liqui d of the Fe56Co7Ni7Zr10B20 alloy upon continuous healing occurs throug h a single stage and the resulting crystallized structure consists of alpha-Fe, Fe2Zr and Fe3B phases containing Co and Ni elements. These F e-based amorphous alloys exhibit good soft magnetic properties and the saturation magnetization, coercive force, permeability at 1 kHz and C urie temperature are respectively 0.96 T, 2.41 A/m, 17700 and 567 K fo r the amorphous Fe56Co7Ni7Zr10B20 alloy annealed for 600 s at 750 K. T he finding of the Fe-based amorphous alloys with good soft magnetic pr operties and high thermal stability of the supercooled liquid is impor tant for future development of ferromagnetic bulk amorphous alloys.