Improving the amorphous forming ability and magnetic properties of FeSiBPCu amorphous and nanocrystalline alloys by utilizing carbon

Abstract

Fe-based amorphous and nanocrystalline alloys with high saturation magnetic flux density (Bs) are highly desirable for electrical and electronic devices, but have’t been industrilized in large scale till now due to their low amorphous forming ability (AFA). In this work, the AFA, thermal stability and magnetic properties of Fe83.3Si4-xB9P3Cu0.7Cx (x = 0, 1, 2, 3 and 4) alloys were investigated systemically. The experimental results show that the AFA, Bs and coercivity (Hc) of this kind of Fe-based amorphous and nanocrystalline alloys are remarkably improved by the substitution of C for Si. With the C content increasing from 0 to 4 at. %, the Bs of this kind of alloys is increased from 1.62T to 1.72T at amorphous state, and increased from 1.78T to 1.86T due to the formation of large volume fraction of α-Fe phase with the grain size from 15 nm to 30 nm. The Si-free FeBPCCu amorphous alloy exhibits the Hc as low as 6.0 A/m. And Si-free FeBPCCu nanocrystalline alloy has a processing window of 9 min for annealing at 500 °C to ensure a comprehensive magnetic property. This work is believed to be helpful to overcome the dilemma of AFA and Bs tradeoff of Fe-based amorphous and nanocrystalline alloys.