The effect of Mn and Al dopants on the β-FeSi2 stabilization by a two-step route: Mechanical alloying and annealing

Abstract Al and Mn dopant influence on β-FeSi 2 phase formation was studied using X-ray diffraction and Mossbauer spectroscopy. Samples of Fe 1− x R x Si 2 (R = Al, Mn with 0.00 ≤  x  ≤ 0.12) were prepared by the simultaneous mill of pure Si, Fe and R, under Ar atmosphere followed by an annealing at 1123 K during 4 h at 1.33 × 10 −5  Pa. The results indicate that the addition of Al improved the stabilization of β-FeSi 2 phase, reducing the amount of ɛ-FeSi from 20% to 6%. Also a preferential substitution at the Fe- site II by Mn atoms in β-FeSi 2 can be inferred from the present study. The sequence of phase formation is summarised by two reactions that account for the milling and the annealing effects.