Si microalloying optimizes the thermal stability, crystallization behaviors and magnetic properties of Fe-rich Fe-B-Cu-Hf alloys

Abstract

The new type Fe-rich Fe-B-Cu-Hf alloys show a great of potential applications as the energy-saving soft magnetic materials, due to its especial α-Fe/amorphous dual phases structure contributes to the high saturation magnetization (Ms), permeability (μe) and low loss cost (W), coercivity (Hc). However, these alloys are difficult to be used actually with the uniform α-Fe/amorphous dual phases structure, on account of the poor glass forming ability (GFA) and the difficulty of crystallizing α-Fe away from the Fe-B compounds precipitation. Therefore, the effects by Si substituting of minor B on GFA, thermal stability, crystallization behaviors and magnetic properties in Fe86B13−xSixCu0.4Hf0.6 alloys have been researched. The results show that Si microalloying is prominent and the ribbons with entire amorphous can still be easily fabricated as Si content is less than x = 1.0. As x = 0.75 and x = 1.0, the amorphous alloys have a two-step crystallization process and the uniform α-Fe/amorphous dual phases structure is easy to be fabricated. After annealing, the crystallized ribbons show a quick increasing trend of Ms values and reach to the maximum approximately 208 emu/g as the annealing temperature is near Tp1, and Hc values are effectively decreased by an auxiliary annealing process applied the magnetic field. The new developed Fe-B-Si-Cu-Hf system alloys with excellent soft magnetic properties show a great application prospect as the novel Fe-based soft magnetic materials.