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以丙烯为气源,在800℃~1200℃进行化学气相沉积热解碳。研究了温度、压力和滞留时间对沉积速率和气相产物的影响。采用磁悬浮天平原位实时称量反应过程中的固相产物进行动力学研究;采用气相色谱和质谱联用半定量分析了反应过程中的气体产物。动力学研究结果表明,800℃~1000℃内活化能为137 kJ/mol±25 kJ/mol,沉积过程为化学动力学控制;高于1000℃时,沉积行为由气相分子的传质和气相成核控制。压力和滞留时间对沉积速率的影响说明,热解碳是经过一系列气相反应和固体表面反应后获得。气相产物分析说明,不同控制机制时形成热解碳的主要物质不同。在此基础上提出了丙烯分解形成热解碳的机制。
Using propylene as the gas source, chemical vapor deposition pyrolytic carbon was carried out at 800 ℃ ~ 1200 ℃. The effects of temperature, pressure and residence time on the deposition rate and gas phase product were investigated. The solid-phase products were weighed in-situ by magnetic levitation balance in-situ for the kinetics study. The gas products in the reaction process were analyzed semi-quantitatively by gas chromatography and mass spectrometry. The kinetic study shows that the activation energy is 137 kJ / mol ± 25 kJ / mol at 800 ℃ to 1000 ℃, and the deposition process is controlled by chemical kinetics. When the temperature is higher than 1000 ℃, the deposition behavior is controlled by the gas phase molecular mass transfer and gas phase formation Nuclear control. The effect of pressure and residence time on the deposition rate shows that pyrolytic carbon is obtained through a series of gas phase reactions and solid surface reactions. Analysis of the gas phase products shows that different control mechanisms form the main material of pyrolytic carbon. Based on this, the mechanism of pyrolytic carbon formation by propylene was proposed.