Effects of B and Si contents on glass-forming ability and soft-magnetic properties in (Co0.89 Fe0.057 Nb0.053) 100-x (B0.8 Si0.2)_x glassy alloys

The effects of B and Si contents on the glass-forming ability (GFA) and soft-magnetic properties of (Co0.89 Fe0.057 Nb0.053) 100-x (B0.8 Si0.2) _x (x=22-30) alloys were investigated. The thermal stability of the supercooled liquid increased with increasing the B and Si contents from x=24 to 28, and accompanying the decreases of liquidus temperature of alloys. As a result, The (Co0.89 Fe0.057 Nb0.053) 100-x (B0.8 Si0.2)_x bulk glassy alloys with diameters up to 3.5 mm were synthesized in the composition range of x=24-28. In addition to high GFA, the Co-based glassy alloys exhibit excellent soft-magnetic properties as well, i.e., moderate saturation magnetization of 0.51-0.72 T, low coercive force of 0.4-1.5 A/m, and high initial permeability of 22 340-29 570 at 1 kHz under a field of 1 A/m.