Structural-phase composition of iron-containing high carbon composites with fullerite and graphite obtained by mechanosynthesis

Abstract

In the present paper, X-ray diffraction, scanning electron microscopy, Mossbauer, Raman and X-ray photoelectron spectroscopy and thermal analysis have been used for the comparative studies of composites fullerite-Fe and graphite-Fe containing 75 at% of carbon and obtained by the mechanosynthesis method. The synthesized materials are nanoscale powders. Depending on the time of mechanosynthesis and a used form of carbon, the phase composition of the composites is significantly different. It is shown that compared with graphite, fullerite is characterized by higher stability in the composition of iron-containing mechanocomposites. The sequence of the fullerite structural changes during mechanosynthesis is as follows: fullerite → amorphous fullerite-like phase → amorphous carbon. When fullerenes are retained, carbides are not formed in the system fullerite-Fe. After the formation of amorphous carbon, the compared composites fullerite-Fe and graphite-Fe have the same composition (Fe3C, Fe7C3, paramagnetic P-phase and amorphous carbon). The stability of the mechanically synthesized phases at heating has been studied.