Optimizing the glass forming ability and soft magnetic properties of FeNiB nanocrystalline alloys through carbon addition

Fe-based nanocrystalline alloys with high saturation magnetic flux density ( B s ) show significant potential for electrical and electronic applications. However, their large-scale industrial production remains challenging due to limited glass forming ability (GFA). In this work, we systematically investigated the GFA, thermal stability and soft magnetic properties of Fe 85-x Ni 2 B 13 C x (x = 0, 1, 2, 3, 4) alloys. The experimental results indicated that appropriate carbon addition can significantly enhance both GFA and soft magnetic properties. Specially, when the carbon content exceeds 2 at. %, the as-spun alloy ribbons retain a fully amorphous structure at a wheel speed of 40 m/s. As the carbon content increases from 0 to 4 at. %, T x1 rises from 628 K to 688 K and T x2 increases from 748 K to 768 K, while the C2 alloy maintains a substantial Δ T over 104 K. After rapid annealing at 753 K for 6 s, the Fe 83 Ni 2 B 13 C 2 alloy exhibits improved soft magnetic properties, achieving B s of 1.87 T and H c of 8.2 A/m. This research provides valuable insights into the development and practical industrial application of Fe-based soft magnetic nanocrystalline alloys with high B s . • The carbon addition can substantially improve the GFA of the Fe 85-x Ni 2 B 13 C x alloy system. • The thermal stability of the amorphous phase is significantly enhanced by the addition of carbon. • After rapid annealing at 753 K for 6 s, the Fe 83 Ni 2 B 13 C 2 alloy exhibits a high B s of 1.87 T combined with an H c of 8.2 A/m.