Effect of co addition on the phase structure and magnetic properties of Fe-Si-Al alloys

(Fe_1-xCo_x)₈₅ Si_9.6Al_5.4 (x=0, 0.05, 0.10, 0.15, 0.20) nanocrystalline flakes with large aspect ratio have been prepared by high-energy planetary ball milling method from melt spun ribbons. Annealing at 773 K for 30 min has been employed to the as-milled powder under the protection of nitrogen. The annealed powder is then mixed with resin to get toroidal samples of Φ19 mm × Φ10 mm × 3 mm at 30 MPa. The effects of Co addition on the phase structure and magnetic properties have been discussed detailed. The results show that the Co addition doesn't change the phase structure of alloy ribbons. However, The Curie temperature has been greatly increased by Co addition; the maximum saturation magnetization is achieved when x=0.15. The toroidal samples show a good anti electromagnetic interference (EMI) performance at about 1 GHz. The cutoff frequency reaches 1.154 GHz when x=0.15.