Structural and magnetic properties of mechanically alloyed FeCo powders

The Fe 100 - x Co x ( x = 30 , 45, 50, 60 wt.%) alloys with average grain size of 10 nm were prepared by a mechanical alloying of the elemental Fe and Co powders using a high-energy ball mill. The prepared alloys were characterized by X-ray diffraction, Mössbauer spectrometry, TEM and magnetic (VSM) measurements. The lattice parameter, saturation magnetization and coercivity were analyzed as a dependence on the Co content. The average hyperfine magnetic field value of about 35 T suggests that the disordered BCC Fe–Co solid solution is formed after 30 h of milling. The ordering (transformation from α -BCC to B2 structure) below the temperature 720 ∘ C after cooling was confirmed by DSC in all compositions with the exception of Fe 70 Co 30 .