Procedure for the measurements of lattice parameters and crystallite sizes of carbon materials by X-ray diffraction

Abstract

Purpose: The purpose of this procedure is to standardize the procedure for the X-ray diffraction measurements of lattice parameters and crystallite sizes of carbon materials. This specification is expected to be used to characterize the structure not only in research laboratories but also in companies producing and using carbon materials. By utilizing the present procedure, more reliable and reproducible structural parameters could be measured, even though some of the determined parameters do not satisfy their exact scientific meanings. For example, the values of measured crystallite sizes depend not only on size of crystals but also on the strain in the crystals.
Abstract: This specification has been called the “Gakushin” method and has been commonly used in Japan. The method gave reliable values of lattice constants and crystallite sizes of carbon materials having a relatively high degree of graphitization. The diffraction peaks 002, 004, 110, 112 and 006 enabled us to compare data measured in different laboratories. The principal points of this specification are as follows: 1) the diffraction profiles observed must be corrected for the line broadening due to different intensity factors, such as X-ray absorption, Lorentz-polarization factors and the atomic scattering factor; 2) an internal standard of silicon must be used in order to avoid the shifting and broadening of diffraction profiles mainly due to the instrument used; and 3) a mixture of carbon sample with standard silicon must be packed in a thin sample holder for X-ray diffraction (0.2mm thickness).