US Patent 7357844 Soft magnetic metallic glass alloy

Disclosed is a soft magnetic Fe—B—Si-based metallic glass alloy with high glass forming ability which has a supercooled-liquid temperature interval (ΔTχ) of 40 K or more, a reduced glass-transition temperature (Tg/Tm) of 0.56 or more and a saturation magnetization of 1.4 T or more. The metallic glass alloy is represented by the following composition formula: (Fe1-a-bBaSib)100-χMχ, wherein a and b represent an atomic ratio, and satisfy the following relations: 0.1≦a≦0.17, 0.06≦b≦0.15 and 0.18≦a+b≦0.3, M is one or more elements selected from the group consisting of Zr, Nb, Ta, Hf, Mo, Ti, V, Cr, Pd and W, and χ satisfies the following relation: 1 atomic % ≦χ≦10 atomic %. The present invention overcomes restrictions in preparing a metallic glass bar with a thickness of 1 mm or more from conventional Fe—B—Si-based metallic glasses due to their poor glass forming ability, and provides a high saturation-magnetization Fe—B—Si-based metallic glass allowing the formation of bulk metallic glass, which serves as a key technology for achieving a broader application fields of metallic glass products.