【摘要】 通过乙炔和甲烷与氧的化学平衡计算和化学传递反应的机理来模拟碳的气化和沉积的温度范围,结果表明,降低压力有利于降低碳沉积的温度范围。对于C-H体系,在常压下(1bar)发生碳沉积的化学传递反应的温度范围为2 800 K→1 600 K,而在低压下(0．01bar),温度范围为2 000 K→1 250 K,这个结果与文献中低压下化学气相沉积合成金刚石的实验数据相吻合。本文提出的模型和计算结果的意义在于,通过对一组化学传递反应器中温度的调节可以较为精确地控制碳沉积过程的过饱和度,从而适应于合成金刚石或碳纳米管的需要。本文所定义的模型和方法可以推广到C-O和C-H-O等体系碳的化学气相沉积的模拟计算。更多还原

【Abstract】 The temperature range of the etching and deposition of carbon were simulated from the chemical equilibrium calculations of methane and acetylene with oxygen based on a mechanism of chemical transport reactions. The results showed that, a reduction of pressure would reduce the temperature range of the carbon deposition. The primary calculation results showed that, for the C-H system, the conditions for the carbon deposition via the chemical transport mechanism are: at an atmospheric (1bar) condition, the temperature range is 2 800→1 600 K, while at a vacuum condition (0. 01 bar) , the temperature range is 2 000→1 250 K. The above results agree well with the experimental data in literature of diamond synthesis by chemical vapor deposition at low pressure. The significance of the defined model and the calculated results in this paper is that the supper-saturation of the carbon in the vapor phase can be more accurately controlled through the adjustment of temperature of a chemical transport reactor to meet the needs of diamond and carbon nano-tube synthesis. The model and the method defined in this paper can be further extended to the simulation of chemical vapor deposition of C-O and C-H-O systems.更多还原