Synthesis of crystalline beta-FeSi2 under high-temperature and high-pressure.

In this paper, we report the synthesis of crystalline beta-FeSi2 via the reaction of Si and Fe powders under high-temperature and high-pressure. X-ray diffraction and Raman scattering results confirm formation of the beta-FeSi2 phase. Scanning electron microscopy, high-resolution transmission electron microscopy, and selected-area electron diffraction patterns show that the beta-FeSi2 phase coexists with Si phase with small nanocrystal sizes. The formation of the beta-FeSi2 phase is a result of Si diffusion into Fe region. The obtained results suggest that the removal of Si phase can be reached through increasing Fe content and prolonging the duration of high-pressure thermal treatment.