Abstract
The preparation of graphite has been worked by pyrolysis of propane gas on a directly heated substrate in the gas pressure range of 5∼200mmHg at the deposition temperature of 2025°C and gas flow rate of 640cm3/min. The formation process and structural features (microstructure, density, and crystal structure) of the pyrolytic graphite were examined on several samples deposited under various gas pressure conditions. The effect of the gas pressure on them is appreciable. At the lower pressures of 5∼10mmHg and the higher pressures above 40mmHg, the formation rate and the structural features vary continuously with the increasing gas pressure. In the pressure range of 20∼30 mmHg, however, the rate of formation drops, and sootiness features its structure. These results with the pressure change are discussed in relation to the convection of the vapor phase.
