Glass-Forming Ability and Magnetic Properties of (Fe^sub 0.80^Co^sub 0.20)^sub 96-x^B^sub x^Si^sub 1^Nb^sub 3-y^Y^sub y^(x=15,17) Amorphous Alloys

The glass-forming ability (GFA) and the magnetic properties of the (Fe^sub 0.80^Co^sub 0.20)^sub 96-x^B^sub x^Si^sub 1^Nb^sub 3-y^Y^sub y^(x=15,17) amorphous alloys have been studied. It was confirmed that GFA is enhanced by replacing Nb with Y. Yttrium gives a complex effect on the magnetization. When Y content is increased, the saturation mass magnetization ([sigma]^sub s^) decreases first. However, the [sigma]^sub s^ then increases and exhibits a maximum ~2 at% Y. The value of [sigma]^sub s^ of the alloy with x=17 and y=2 in an as-quenched state is 211 x 10^sup -6^Wbm/kg , which is slightly larger than that of the Y-free alloy with the same B content. The values of the coercivity of these alloys are less than 10 A/m in an as-quenched state. The coercivity shows a tendency to decrease with increasing Y content, which means the increase of GFA. These results indicate that the partial replacement of Nb by Y in the Fe-Co-B-Si-Nb alloys is useful to the simultaneous achievement of high GFA, high [sigma]^sub s^ , and good soft magnetic properties.