Homogeneous and Heterogeneous Graphitization of Carbon

Abstract

IT is well known that, on heating to temperatures between 1,700° and 3,000° C, some carbons show a continuous and homogeneous development of the three-dimensional structure of graphite, whereas in others the structure does not develop beyond the stage of small regions of ‘turbostratic’¹ order. It has been shown² that graphitization is impeded when there is strong cross-linking between the small ordered regions (which are formed in all carbons at low temperatures), and also when there is random orientation between neighbouring ordered regions. Of these two factors, the latter is the more fundamental. At sufficiently high temperatures, cross-linking is always destroyed²; but, where random orientation exists, no homogeneous graphitization occurs.