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采用化学气相沉积工艺合成了石英玻璃,研究了沉积速率与载料气体之间的关系。利用扫描电子显微镜观察火焰中SiO2粒子微观形态和尺寸。通过对SiCl4水解、氧化反应速率的计算表明:在一定温度下,当同时存在充足的H2O和O2时,SiCl4氧化反应速率远高于水解反应速率。当载料气体为H2,SiCl4流量为25g/min时,观察火焰中SiO2粒子的微观形态发现存在大量非球状无定形聚集体,表明SiCl4未反应完全,沉积速率较低,约为220～240g/h。同样SiCl4流量下,采用O2作为载料气体时火焰中颗粒均为球状,SiCl4全部反应,沉积速率较高,达到300～350g/h。当SiCl4流量为15g/min时,载料气体的改变对SiO2粒子形态和尺寸没有影响,SiCl4可以全部反应,沉积速率基本相同。当SiCl4流量较高(25g/min)时,载料气体对反应机理和沉积速率有显著影响,若要SiCl4在极短时间内完全反应生成球状SiO2粒子,需选择O2作为载料气体,充足的O2保证SiCl4可以通过氧化反应全部反应完毕,沉积速率相应提高。
Abstract：The relationship between the carrier gas and the deposition rate of the synthesis silica glass by chemical vapor deposition method was investigated.The morphology and size of silica particles were characterized by scanning electron microscopy.According to calculations,the oxidation rate of silicon tetrachloride(SiCl4) is much higher than the hydrolysis rate at certain temperatures when enough H2O and O2 is present.When the carrier gas is H2 and the flow rate of SiCl4 is 25 g/min,there are many non-spherical amorphous aggregates in the flame.This indicates that the SiCl4 does not react completely,and the deposition rate is 220-240 g/h.At the same flow rate,there are all spherical particles in the flame when O2 is used as the carrier gas.The SiCl4 can react completely and the deposition rate is 300-350 g/h.When the SiCl4 flow rate is 15 g/min,the change of the carrier gas has little effect on the particle microscopic morphology and size,and the final deposition rate is equal.The results show that the carrier gas has a significant effect on the deposition rate and reaction mechanism at a higher flow rate of SiCl4(25 g/min).It is necessary to use O2 as carrier gas to transform all SiCl4 into spherical silica particles in a very short time.Under the condition of superfluous O2,SiCl4 can react completely through oxidation,and the deposition rate is increased correspondingly.
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基本信息:
中图分类号:TQ171.1
引用信息:
[1]徐驰,顾真安,饶传东.载料气体对化学气相沉积合成石英玻璃沉积速率的影响(英文)[J].硅酸盐学报,2009,37(10):1796-1802.
2009-10-15
2009-10-15