Bulk Glassy Co₄₃Fe₂₀Ta_5.5B_31.5 Alloy with High Glass-Forming Ability and Good Soft Magnetic Properties

Abstract

A new Co-based bulk glassy alloy Co₄₃Fe₂₀Ta_5.5B_31.5 exhibiting a large supercooled liquid region before crystallization and good soft magnetic properties was synthesized by the copper mold casting method. The glass transition temperature (T_g) is 910 K and the supercooled liquid region (ΔT_x) reaches 70 K . The high thermal stability of the supercooled liquid enabled us to produce bulk glassy alloys with diameters up to 2 mm. These bulk glassy alloys exhibit good soft magnetic properties, i.e., saturation magnetization of 0.5 T, very low coercivity of 0.9 A/m and very high permeability of 40000 at 1 kHz. It is noticed that the diameter of 2 mm is the largest value for Co-based bulk glassy alloys reported up to now. The success of forming the large-scale size Co-based bulk glassy alloy with high thermal stability of supercooled liquid and good soft magnetic properties is encouraging for future uses of bulk amorphous soft magnetic materials.