X-ray Studies on Electro-graphitized Carbon Products

II, The Size of Graphite Crystallites

Abstract

The size of graphite crystallites in various electro-graphitized carbon products was measured by using a recording χ-ray diffractometer. A measured profile of χ-ray diffraction of a carbon product is a compound profile of graphite crystallites of different carbon bases, if the product was made from a mixture of different carbon materials. The calculated values using the half-intensity width of the compound profile may not give the true mean size of crystallites. However, the size of graphite crystallites was measured with the conventional method in order to obtain an approximation of crystal size in commercial electro-graphitized carbon products.
The size of graphite crystallites of electro-graphitized carbon products largely depends on the original carbon materials used and is not necessarily the same in the products having the same degree of graphitization. Although thickness L_c and width L_a of graphite layer of electro-graphitized coke base products, such as electrodes and anodes, were not parallel with the degree of graphitization, the thickness of three dimensional crystal layer L_hkl of these products grew large with the degree of graphitization.
Even though carbon brushes are usually made of a mixture of different carbon materials and the measured values of crystal size do not give the true dimensions, a useful information could be deduced from the measured values in comparing with the degree of graphitization of the same products. Thus one can estimate the relative size of carbon black particles used in the brushes of carbon black base.