Excellent soft magnetic properties and enhanced glass forming ability of Fe-Si-B-C-Cu nanocrystalline alloys

In the present investigation, the glass forming ability (GFA), thermal stability, and soft magnetic properties of Fe85Si6-xB8Cu1Cx alloys are investigated by the substitution of C for Si. It was found that the GFA of C-containing alloys is remarkably enhanced when a certain amount of Si is replaced by C in a C-free alloy. The temperature interval between the first and second crystallization temperatures is also improved by C addition and reaches a maximum value of 169 °C for the as-spun Fe85Si2B8Cu1C4 amorphous alloy. The Fe85Si4B8Cu1C2 nanocrystalline alloy exhibits the best soft magnetic properties with the highest saturation magnetic flux density (Bs) of 1.95 T and the lowest coercivity (Hc) of 4.1 A/m, which corresponds to the highest grain number density (Nd). The high GFA, large annealing window, low cost, and excellent soft magnetic properties enable the Fe85Si2B8Cu1C4 nanocrystalline alloy as a material with wide applicability. Moreover, this work is highly beneficial in balancing the relationship between a high Bs and sufficient GFA in the production of Fe-rich nanocrystalline alloys.