以丙烯为碳源, 利用磁悬浮天平热重系统研究了化学气相沉积热解碳的原位动力学, 采用气质联用仪对热解气相冷凝物进行了定性和半定量分析. 结果表明: 当稀释比为4, 总压力为6kPa, 丙烯流量为20sccm时, 丙烯在850～1100℃之间的热解反应表观活化能为(201.9±0.6)kJ/mol, 沉积过程为气相均相反应控制, 高温时冷凝物以单环芳烃为主, 低温时主要为双环和多环芳烃; 在900和1000℃下, 丙烯分压在0.3～6.5kPa范围内的热解为一级反应; 由于受有效反应时间和丙烯通量的共同作用, 沉积速率随滞留时间的延长先增大后减小, 在900℃下滞留时间为0.6s时出现最大值.
The deposition kinetics of pyrocarbon by chemical vapor deposition (CVD) from propylene was investigated by in situ measurements of deposition rates which were measured by Magnetic Suspension Balance TG system. The gas phase products that collected by a liquid nitrogen cold trap were analyzed by GC-MS. The apparent activation energy is (201.9±0.6)kJ/mol in the range from 850℃ to 1100℃, where dilution ratio α is 4, total pressure is 6kPa and the flow rate of propylene is 20sccm, and the deposition kinetics is controlled by homogenous reactions. The main products of gas phase are single ring aromatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) at high and low temperatures, respectively. Through the investigation of dependence of propylene partial pressure (0.3--6.5kPa) on deposition rate in 900℃ and 1000℃, it can be concluded that the decomposition of propylene is a first order reaction. Related to both of the effective reaction time and the flow rate of propylene, the maximum of the deposition rate is found at residence time of 0.6s.
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