Note: Graphite fibres can be obtained by graphitization heat treatment of carbon fibres if these consist mostly of graphitizable carbon. If the h,k,ldiffraction lines are difficult to recognize because they are of minor intensity, the mean interlayer spacing $\text{c}/2$ can be used as indication for the presence of a graphitic structure. The $\text{c}/2$ value of $0.34\text{nm}$ is generally considered as an upper limit for synthetic graphite.