【摘要】 以液化石油气为碳源气体,采用多元耦合场CVI工艺方法快速制备了炭/炭复合材料。在自制冷壁CVI炉中,使用普通炭毡作为炭纤维预制体,设置特殊的导电发热层,沉积温度为650~1050℃,系统的气氛压力为0.1~30kPa,流量为0.1~0.5m3/h,沉积时间12h的条件下可将预制体一次性快速增密至1.75g/cm3。XRD分析表明:该材料经过2300℃,2h高温石墨化处理,其石墨化度(g)可达到61.3%,晶粒尺寸达到16.1nm。PLM分析表明所得材料偏光形貌表现为光滑层(SL)结构,SEM形貌照片测算可知热解炭沉积速率在6.6μm/h以上。分析了炭/炭致密化的过程和热解炭的沉积机理,说明多元耦合场加速了热解炭的沉积,缩短了致密化时间,降低了成本。更多还原

【Abstract】 Based on the multi-coupling fields CVI process,C/C composites were fast fabricated with liquefied petroleum gas as the precursor.In the self-designed cold-wall CVI reactor,the carbon fiber preform was densified up to 1.75g/cm~3 with deposition temperature 650～1050℃,system gas pressure 0.1～30kPa and flow rate 0.1～0.5m~3/h within 12 h at one cycle.XRD result shows the C/C composites gain graphitization degree 61.3% and crystalline size 16.1nm after 2 300 ℃,2h HTT(high temperature heat treatment).PLM(polarized light microscope) analysis indicates the pyrolytic carbon of C/C composite is smooth laminar(SL).According to SEM image,the deposition rate of pyrolytic carbon can be measured and calculated over 6.6μm/h.By analyzing densified process of the C/C composites and densification mechanism of pyrolytic carbon,the integration effect of the electromagnetic field,thermal gradient and concentration field are interpreted.And the effect accelerates pyrolytic carbon deposition,shortens the densified time and lowers the cost.更多还原