Cone-helix growth forms of graphite

Abstract

Various kinds of filamentary growth of graphite from the gas phase have structures that can be interpreted in terms of curved basal sheets of graphite arranged in the form of cone-helices. In these arrangements successive spiral basal layers are rotated relative to one another, but only those geometries occur in which this rotation is a multiple of 60° (thus restoring the graphite basal stacking in the “c” direction) or alternatively 21.8° which is one of the optimum coincidence configurations for “c” axis rotation faults in graphite. This type of growth form occurs in solid filaments prepared under various experimental conditions, and also in hollow filamentary tubes. There is some evidence that it might also occur in semi-fibrous and spherulitic forms of crystallization from metal solution.