Phase stabilization in the Fe1−xMnxSi2 system induced by ball milling

Phase formation in the Mn doped iron disilicide system Fe1−xMnxSi2 with 0.00 ≤ x ≤ 0.24 was studied using X-ray diffraction and Mössbauer spectroscopy. Samples were prepared at room temperature in Ar atmosphere by two different routes. The first one involved the simultaneous mill of the pure elements, and the second one the milling in two steps, first the premixture of metals and then the addition of Si. Both routes produced β-FeSi2, ɛ-FeSi and α-FeSi2 phases. In the first case, the segregation of MnSi and Si was also observed. The diffraction results and the obtained set of hyperfine parameters supported the coexistence of β-FeSi2, α-FeSi2 and ɛ-FeSi. The relative phase composition depended on the preparation route, being the obtained fraction of the ɛ-FeSi smaller when the second preparation route was followed. It seemed that the previous formation of a Fe1−xMnx alloy before to the silicide overcomes the chemical driving forces.