Decomposition of fullerite during the high-temperature heating

Abstract

X-ray diffraction, scanning electron microscopy, Mossbauer and Raman spectroscopy have been used for studying structural changes arising due to the thermal decomposition of fullerite C60/70 at heating to 1600 °C in CO medium. The scheme of the structural changes of fullerite at the initial graphitization temperatures is given. It is shown that the thermal disordering of fullerite with the formation of a fullerite-like amorphous phase is observed at heating above 900 °C. The subsequent ordering of carbon takes place at the temperature of 1600 °C with the formation of a graphite-like amorphous phase. The graphitization process proceeds with the formation of turbostratic carbon and crystalline graphite with a low degree of ordering. The nature of the formation of carbon substructures is considered. Carbon structural changes are accompanied by morphological changes. Comparative studies of changes in the structure of soot, graphite and glass-like carbon during heating have been presented. The catalytic effect of Fe on the processes of the disordering of initial fullerite is considered. It is shown that in the Fe presence the temperature of the phase transition ‘fullerite-graphite’ decreases from 1600 to 760 °C. Graphite, formed after the Fe3C decomposition, is characterized by a higher degree of ordering.