X-Ray studies of graphite formed by decomposing silicon carbide

The structural changes which occur when single crystals of α silicon carbide (6H) are heated in vacuo, have been studied by using X-ray diffraction methods. The crystals were heated in an induction furnace for an hour to ~2280°C. This resulted in the formation of pseudomorphs which retained the morphology of the original SiC crystals but had a complicated structure which was made up of various stages in the development of a graphite lattice. A definite relation was found between the lattice of SiC and the structure of the resultant pseudomorph. The complex nature of the matrix is described and a possible mechanism of decomposition is suggested.