Preparation of gas-atomised amorphous soft magnetic powders with high saturated magnetisation above 1.25 T realised by senary Fe₇₃Si_9−xB₁₀P₅C₃Mo_x alloys with abnormal glass-forming ability

Abstract

Micron-scale powdered amorphous soft magnetic materials are highly pursued for miniaturised 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 (GFA) of amorphous soft magnetic alloys has hindered the preparation of amorphous soft magnetic powders through gas atomisation. Here, we present the development of amorphous soft magnetic alloys based on Mo-containing alloys with abnormal GFA, and demonstrate preparation of fully amorphous soft magnetic powders fabricated through the conventional medium-coolingrate gas atomisation process. Our Mo-containing Fe 73 Si 9−x B 10 P 5 C 3 Mo x alloy showed fully amorphous state in a ribbon form with thickness up to 179 μm. Gas atomisation performed using the alloy produced fully amorphous powder with diameter up to 75 μm, while possessing high saturation magnetisation of 1.25 T.