X-Ray Study of the Graphitization of Carbon Black

A picture of the early stage of graphitization of a carbon black has been obtained from an x-ray study of a Fine Thermal (FT) carbon black heated for two hours at 2300°C. Nearest neighbor pairs of layers take on the graphite relation independently, producing both ABA and ABC sequences. There are two nearest neighbor layer spacings 3.35 A and 3.44 A corresponding to pairs with the graphite relation and pairs with random orientation. The (00l) peaks must be corrected for the distortion broadening resulting from the two spacings, to obtain the parallel layer group thickness Lc. The probability for the ordering of nearest neighbor layers P1 is defined as the ``degree of graphitization.'' A logarithmic plot is used for a rapid determination of P1 and the layer diameter La from the modulated two dimensional (hk) reflections.