Effect of Mo addition on thermal stability and magnetic properties in FeSiBPCu nanocrystalline alloys

The glass forming ability, thermal stability, microstructure, and magnetic properties of Fe83.3(Si4B8P4)16-xCu0.7Mox (x = 0, 0.5, 1, and 1.5) alloys are studied to investigate the influence of Mo addition. With increasing Mo content, the negative mixing enthalpy (Delta Hmix) increases and the Delta parameter (delta) de-creases, which leads to a decline in the glass forming ability. The secondary crystallization temperature increases continuously with increasing Mo content. A small amount of Mo improves sufficiently the thermal stability of the alloy system, which can bear higher temperatures (up to 520 degrees C) for longer time (up to 40 min) without the formation of compounds because of their increased activation energy. The saturation magnetic flux density (Bs) decreases from 1.78 to 1.68 T with increasing Mo content as a result of the lower volume fraction of the alpha-Fe phase. Optimum magnetic properties with Bs = 1.74T and Hc = 8.2A/m are achieved in Fe83.3(Si4B8P4)15-Cu0.7Mo1 ribbon.