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以丙烯和氩气为气源,在800～1200℃,1～15 kPa和25～500 sccm条件下进行化学气相沉积热解碳,采用磁悬浮天平实时称量热解碳的生成量进行动力学研究。结果表明,1000℃以下,化学反应控制沉积过程,乙炔的生成为限速步骤;当温度高于1000℃时,转变为气相传质控制,温度是影响沉积机理最重要的热力学参数。压力和滞留时间对沉积速率的影响说明热解碳是通过一系列气相连续反应后形成的。采用实验测得的活化能137±25 kJ/mol和丙烯分压一级反应级数,确定了总的动力学方程式,并用实验结果验证了其有效性。
Pyrolysis of carbon by chemical vapor deposition at 800 ~ 1200 ℃, 1 ~ 15 kPa and 25 ~ 500 sccm with propylene and argon as the gas source, and kinetics of the pyrolysis of carbon using a magnetic suspension balance . The results show that the chemical reaction controls the deposition process and the formation of acetylene is the rate limiting step below 1000 ℃. When the temperature is higher than 1000 ℃, it turns into vapor mass transfer control. The temperature is the most important thermodynamic parameter that affects the deposition mechanism. The effect of pressure and residence time on the deposition rate indicates that pyrolytic carbon is formed by a series of gas-phase continuous reactions. The experimental kinetic energy of 137 ± 25 kJ / mol and the first order of partial pressure of propylene were used to determine the total kinetic equation. The experimental results verify its effectiveness.