Preparation and soft magnetic properties of Fe-Si-B-C-N amorphous/nanocrystalline alloys

Abstract

We nitrided high-purity thin iron sheets using a plasma nitriding process and then measured the actual nitrogen content of the nitrided sheets using an oxygen-nitrogen analyzer. The amorphous alloys of Fe_82.5-xSi₂B₁₅C_0.5N_x (x=0–0.5 at%) were successfully prepared. The effect of the crystallization behavior of the amorphous alloys on the soft magnetic properties was investigated. The results show that the amorphous forming ability of the alloy can be improved by adding an appropriate amount of nitrogen, and the atoms of the alloy can be ordered by N element. However, excessive nitrogen will reduce the amorphous forming ability of the alloy. Appropriate nitrogen doping reduces coercivity (H_c), and the loss of saturation magnetic flux density (B_s) is minimal due to trace doping. After heat treatment, Fe_82.45Si₂B₁₅C_0.5N_0.05 exhibits the lowest H_c of 2.1 A/m following annealing at 380°C, while B_s remains around 1.71 T. This represents excellent overall soft magnetic properties for a composition that has only undergone a simple annealing process and has not been doped with large atoms.