Evolution under thermal annealing of Mn-doped iron disilicides obtained by ball milling

Abstract

Phase formation in the Mn doped β-FeSi2 system (Fe1− xMn x Si2 with 0.00≤x≤0.24) was studied using X-ray diffraction and Mossbauer spectroscopy. Samples were prepared by the simultaneous mill of pure Si, Mn and Fe under Ar atmosphere followed by an annealing at 1,123 K during 4 h at 1×10−7 Torr. After milling, an admixture of β-FeSi2, α-FeSi2 and ɛ-FeSi phases was present while α-FeSi2 disappeared after annealing, resulting β-FeSi2 the main phase. Depending on Mn concentration, small amounts of ɛ-FeSi and Si segregation were also observed. A preferential substitution of Fe atoms by Mn ones in the FeII site of the β-FeSi2 regular lattice was inferred from the Mossbauer results.