Improved glass formability of Fe 76 Si 9−x B 10 P 5 C x amorphous alloys through carbon content optimization for gas atomization

Abstract

Micron-scale powdered amorphous soft magnetic materials are being aggressively pursued for miniaturized and high-efficiency power inductors working at high frequencies due to their excellent soft magnetic properties such as extremely low coercivity and high electrical resistivity originated from the disordered atomic structures and zero magnetocrystalline anisotropy. However, the limited glass forming ability of amorphous soft magnetic alloys has hindered the preparation of amorphous soft magnetic powders through gas atomization. Here, we present the development of amorphous soft magnetic alloys based on carbon containing alloys with abnormal glass forming ability, and demonstrate the preparation of fully-amorphous soft magnetic powders fabricated through the conventional medium-cooling-rate gas atomization process. Our carbon-containing Fe₇₆Si_9−xB₁₀P₅C_x alloy showed exceptional glass forming ability, characterized by a ΔT_x (T_x−T_g) value of 33 °C, and can achieve a fully amorphous state in ribbon form with a thickness of up to 68 μm. Gas atomization was performed using the alloy produced fully amorphous powder with diameter of up to 45 μm, while possessing high saturation magnetization of 167.8 emu/g (1.53 T) and coercivity of 2.3 Oe.