X-ray diffraction patterns of graphite and turbostratic carbon

Abstract

To identify the influence of microstructural variation on the X-ray diffraction intensities, X-ray diffraction patterns of hexagonal graphite (h-graphite) and turbostratic carbon (t-carbon) were simulated by using the general Debye equation. The numeric density of interatomic distance (NDID) is sensitive to the size and microstructure of a crystallite, so that it is used to characterize the structures of h-graphite and t-carbon. The dependence of the diffraction angles and full width at half maximums (FWHMs) of diffraction lines on the crystallite size and distortion factors is examined by computer simulation. The distortion factors for t-carbon, including rotation, translation, curvature, local positive fluctuation of interlayer spacing of graphene layers and fluctuation of atomic positions, have different influence on the NDIDs, hence on the X-ray diffraction patterns. The simulation results indicate that the diffraction angles and FWHMs of diffraction lines cannot be simply used to characterize the lattice parameters and crystallite sizes of t-carbon.