Soft Magnetic Properties of Amorphous ring Cores Prepared via Spark Plasma Sintering Using Fe-based Amorphous Powders (Fe, Co)_68.7(C, Si, B, P)_24.5(Mo, Al)_6.8

An Fe-based amorphous alloy (Fe, Co)_68.7(C, Si, B, P)_24.5(Mo, Al)_6.8 was prepared as amorphous ribbons (~ 25 μm thick) and amorphous rods (Ф3 mm), which were crushed and sieved to form powders with different shapes and particles smaller than 53 μm: amorphous flake powders made from crushed ribbons and amorphous irregular powders made from crushed rods. Both powders were consolidated via spark plasma sintering into dense ring cores with a relative density exceeding 90%; this high density is attributed to the Newtonian flow within the temperature range of the amorphous powder’s supercooled liquid region. Excellent soft magnetic properties originating from the amorphous nature and high density of the ring cores were confirmed. Additionally, due to electrical isolation between the powder particles, the eddy current loss of the amorphous ring cores made from the SiO₂-coated amorphous flake powder was significantly reduced to 4.86 W/kg (at Bm = 100 mT, 1 kHz).