Bulk Glassy Fe–Mo–Ga–P–C–B–Si Alloys with High Glass-Forming Ability and Good Soft Magnetic Properties

Abstract

The effect of Mo and Si additions on the glass-forming ability (GFA) of Fe_77−xMo_xGa₃P₁₀C₄B₄Si₂ alloys was investigated. The addition of 2 at%Mo combined with 2 at%Si was found to be effective for the extension of the supercooled liquid region (ΔT_x) defined by the difference between glass transition temperature (T_g) and crystallization temperature (T_x). The ΔT_x value is 33 K for the Fe₇₇Ga₃P₁₂C₄B₄ alloy, and increases to 60 K for the Fe₇₅Mo₂Ga₃P₁₀C₄B₄Si₂ glassy alloy. In addition, this glassy alloy exhibits a high reduced glass transition temperature (T_g⁄T_l) of 0.6. The large ΔT_x and high T_g⁄T_l enabled us to prepare the Fe₇₅Mo₂Ga₃P₁₀C₄B₄Si₂ bulk glassy alloy successfully with a diameter of 2 mm and high saturation magnetization (I_s) of 1.27 T. The Fe₇₅Mo₂Ga₃P₁₀C₄B₄Si₂ glassy alloy also exhibits good soft magnetic properties, i.e., high effective permeability at 1 kHz of 1.1×10⁴ and low coercive force of 5 A/m.