High thermal stability of soft magnetic (Fe,Co)-Mo-B-C-P-Si metallic glasses

The effects of metalloids on the thermal stability and magnetic properties of (Fe,Co)-Mo-B-C-P-Si metallic glasses are presented. The alloys exhibit high thermal stability, despite only a 40 K width of the supercooled liquid (SCL) region and a reduced glass transition temperature of 0.55. The amorphous phases and their high saturation magnetization (∼1.44 T) and low coercive field (∼20 A/m) are retained upon long-term annealing in the SCL region. Temperature-time transformation (TTT) studies and investigation of crystallization properties using transmission electron microscopy confirm the beneficial effect of cobalt on the thermal stability, rendering the present alloys promising for scientific study and soft magnet applications.