Influence of small amounts of aluminum and sulfur on magnetic properties in amorphous ribbons

Small amounts of metallic aluminum and aluminum oxide or ferrosulfur were added to the Fe-B-Si alloys. The specimens were prepared with 10∼20mm width and approximately 30μm thickness. Annealings were performed in a magnetic field up to 425°C for 60min in vacuum. The minimum iron loss after annealing was increased by the factor 1.1 ∼ 1.2 by the addition of aluminum and aluminum oxide or sulfur. The annealing temperature which gives the minimum less was 375°C for Fe-B-Si-0.04at%S ribbons, 350°C for Fe-B-Si-0.008at% Al and Fe-B-Si-0.04at%S ribbons. The magnetic domain patterns were observed by SEM.