The sequence of phase formations for elemental powders of
stoichiometric FeSi2 and Fe1-xPtxSi2 (0.03⩽x⩽0.50) mixtures prepared by mechanical alloying at room
temperature in an Ar atmosphere in a horizontal mill is presented.
Sample evolution was followed by means of Mössbauer spectroscopy
and x-ray diffraction. After the milling, the results indicate the
formation of different disordered iron silicides, depending on
milling time. The kinetics of iron silicide formation was also
studied; a diffusion-controlled process with decreasing nucleation
rate was found. In the case of Pt-doped samples, the segregation of
Pt silicides was observed even for the smallest concentration, and
no noticeable incorporation of Pt into the β-FeSi2
lattice could be inferred. Samples were also subjected to annealing
at 1123 K for 4 h to produce ordering in the structures.