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为分析碳源在化学气相渗透过程中的沉积机制,以碳纤维针刺整体毡为预制体,添加丙烯(C_3H_6)的天然气混合气体为碳源,研究了碳源组成对C/C复合材料致密化及热解炭结构的影响。结果表明:相比于以天然气为碳源,以添加了适当比例C_3H_6的天然气为碳源,可有效提高C/C复合材料的致密化速率及密度分布均匀性;同时,有利于生成高织构的热解炭。最优条件(9vol%C_3H_6)下沉积100h后,C/C复合材料的密度和径向密度偏差分别为1.40g/cm~3和0.04g/cm~3,热解炭为均一的粗糙层结构,石墨化度高;而以天然气作碳源时,密度和径向密度偏差分别为1.17g/cm~3和0.07g/cm~3,热解炭为二元带状结构,石墨化度较低;当C_3H_6比例增加到17vol%时,其密度和径向密度偏差分别为1.28g/cm~3和0.10g/cm~3,密度及密度分布均匀性较最优条件下制备的复合材料明显降低。
In order to analyze the deposition mechanism of carbon source during the chemical vapor infiltration process, carbon fiber needle-punched monolithic felt was used as preform and natural gas mixture of propylene (C_3H_6) as carbon source. The effect of carbon source composition on densification of C / C composites And pyrolysis of carbon structure. The results show that compared with using natural gas as carbon source and natural gas with suitable proportion of C_3H_6 as carbon source, the densification rate and density distribution uniformity of C / C composites can be effectively improved. Meanwhile, Pyrolytic carbon. Under the optimal conditions (9vol% C_3H_6) for 100h, the density and radial density deviations of C / C composites were 1.40g / cm ~ 3 and 0.04g / cm ~ 3, respectively. , While the graphitization degree is high. When natural gas is used as a carbon source, the density and radial density deviations are 1.17g / cm ~ 3 and 0.07g / cm ~ 3, respectively. The pyrolytic carbon is a binary ribbon structure with a higher degree of graphitization When the proportion of C_3H_6 increased to 17vol%, the density and radial density deviations were 1.28g / cm ~ 3 and 0.10g / cm ~ 3, respectively. The uniformity of density and density distribution was more obvious than the composite prepared under the optimal conditions reduce.