GRAPHITIZATION KINETICS OF FLUIDIZED-BED PYROLYTIC CARBONS

摘要

The graphitization behavior of twelve fluidized-bed pyrocarbons was studied as a function of heat-treatment time and temperature over the range 1350 to 3000°C to investigate the influence of initial microstructure on the graphitization process. The term "graphitization" implies development of the thermodynamically stable hexagonal graphite structure, but is defined more broadly in this work to include any thermally induced structural change whether or not any layer stacking order is attained. A broad range of chemically vapor-deposited microstructures was prepared by spanning a range of deposition conditions including temperatures from 1150 to 1900°C and a variety of propylene and methane concentrations. All-carbon substrates, including glassy carbon microspheres and thin graphite plates, were employed to avoid introduction of impurities which might catalyze graphitization of the coatings during deposition or subsequent heat treatment.