Preparation, infrared spectroscopy, and phase stability of nanosized iron silicide powders

Nanosized powders of iron silicides were prepared by the arc plasma method. These silicide powders were characterized by X-ray diffraction and transmission electron microscopy. The lattice vibrations of nanosized ε-FeSi were investigated by Fourier-transformation infrared spectroscopy and compared with those of bulk FeSi. To determine the stability of different iron silicides, powder mixtures of ε-FeSi and α-FeSi2 were treated thermally in different atmospheres, and at high pressure as well. The different behaviors of α-FeSi2 could be understood by means of the thermodynamics and kinetics of structural transformation in nanosized α-FeSi2 grains.