基于正交试验的天然气CVI工艺优化

Processing parameters optimization of CVI of natural gas based on orthogonal test

在天然气中添加一定比例的丙烯作为碳源气体,进行整体毡预制体的CVI致密;将沉积温度、压力和碳源中丙烯比例作为可调参数,构成三因素三水平的正交试验。试验结果表明,在所选的参数水平下,压力是影响沉积速率的最显著因素,其次为丙烯比例,温度的影响最小;在沉积速率较快的条件下,所得C/C试样的密度不均匀性也较明显。综合对比分析,温度为1323 K,压力为10 k Pa,丙烯比例为20%的条件下,试样不仅具有较快的致密化速率,且有利于后续的沉积致密,为优化的工艺条件。

Densification of the integral felt by chemical vapor infiltration （CVI） process has been performed, using natural gas with a certain amount of propylene（PP） as carbon sources.The effects of deposition temperature （T）, applied pressure （p）and ratio （r） of PP to the natural gas on the deposition rate and densification were investigated by an orthogonal test.Results show that the applied pressure is the prominent factor in determining the deposition rate, and the temperature was the least among them.The inhomogeneity in density of the C/C samples becomes more evident as the deposition rate is high. Overall, the systemic comparisons have led us to obtain the optimum processing conditions ： T= 1323 K,p = 10 kPa, and r = 20%, under which the obtained samples show a high densification rate, which is beneficial for the subsequent deposition.