RAMAN STUDIES OF HEAT-TREATED CARBON-BLACKS

Raman spectra of regular and heat-treated carbon blacks were obtained and used to determine the changes in microstructure due to thermal tre atment. Eight different grades were tested, at five heat-treatment tem peratures ranging from room temperature to 3000 K. The peak at 1345 cm (-1), which has been assigned to symmetric C-C vibrations, is characte ristic of disordered structures and its intensity decreases with incre asing size of the graphitic planes. That band and the 1575 cm(-1) peak characteristic of graphite were analyzed and the ratio of their integ rated intensities was used to estimate the in-plane dimensions of grap hitic crystalline regions. It is found that the size of these microcry stallites increases with temperature. The results of the Raman studies are in good agreement with the data obtained from X-ray diffraction. The temperature-induced changes in crystalline dimensions are explaine d in terms of reorganization of amorphous carbon, layer planes, and mi crocrystallites.