Preparation and magnetic properties of FeCoHfMoBY bulk metallic glasses

Bulk metallic glasses (BMGs) Fe70−xCoxHf5Mo7B15Y3 (x = 0-20 at.%) with a diameter of 3 mm were synthesized by copper mold casting technique. The effect of Co substitution for Fe on the structure, thermal stability and the magnetic properties has been studied by X-ray diffraction (XRD), differential thermal analyzer (DTA) and vibrating sample magnetometer (VSM), respectively. It was found that the substitution of an appropriate amount of Co for Fe can improve the glass forming ability as indicated by the increase in the critical size for glass formation. The wide supercooled liquid region ΔTx (exceeding 50 K) and a high Tg (exceeding 870 K) demonstrated a high thermal stability of the present Fe-based BMGs. In addition, these bulk metallic glasses also exhibit good soft magnetic properties with relatively high saturation magnetization of 45.7-60.7 emu/g, and low coercivity of 1.0-3.6 Oe for the as-cast alloys at room temperature.