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

Nanosized powders of iron silicides were prepared by the are plasma method. These silicide powders were characterized by X-ray diffraction and transmi ssion electron microscopy. The lattice vibrations of nanosized epsilon-FeSi were investigated by Fourier-transformation infrared spectroscopy and comp ared with those of bulk FeSi. To determine the stability of different iron silicides, powder mixtures of epsilon-FeSi and alpha-FeSi2 were treated the rmally in different atmospheres, and at high pressure as well. The differen t behaviors of alpha-FeSi2 could be understood by means of the thermodynami cs and kinetics of structural transformation in nanosized alpha-FeSi2 grain s. (C) 2000 Elsevier Science Ltd.