Bulk Glassy Fe_78-xCo_xGa₂P₁₂C₄B₄ Alloys with High Saturation Magnetization and Good Soft Magnetic Properties

Abstract

The effect of Co on the magnetic properties and glass-forming ability for the Fe_78−xCo_xGa₂P₁₂C₄B₄ glassy alloys was investigated. The addition of 4 to 8 at%Co was found to be effective for the extension of the supercooled liquid region (ΔT_x) defined by the difference between the glass transition temperature (T_g) and crystallization temperature (T_x). The ΔT_x value is 26 K for the Fe₇₈Ga₂P₁₂C₄B₄ alloy and increases to 37 K for the 4 at%Co alloy. Besides, the addition of a small amount of Co was also found to be effective for increasing the saturation magnetization (I_s) and decreasing the coercive force (H_c). These glassy ribbon alloys exhibit good soft magnetic properties of 1.36 to 1.43 T for saturation magnetization and 1.5 to 1.8 A/m for coercive force. The largest saturation magnetization (I_s) is 1.43 T for Fe₇₄Co₄Ga₂P₁₂C₄B₄ alloy. Based on its large ΔT_x, we tried to prepare bulk glassy Fe₇₄Co₄Ga₂P₁₂C₄B₄ rods in a cylindrical form with different diameters. The glassy single phase was obtained in the diameter of 0.5 and 1.0 mm. These bulk glassy alloys also exhibit high saturation magnetization of about 1.42 T.