化学液气相渗透致密快速制备炭/炭复合材料

探索了一种的炭/炭制备方法-快速化学液气相渗透致密(CLVD),沉积时间3h内可获得密度达1.74g/cm3的炭/炭材料.预制体为环形炭毡制件(160mm×80mm×10mm),以液态低分子有机物(CYH和KEE)作炭源前躯体,将预制体浸泡在液体炭源前驱体中,利用辐射加热,在预制体范围内造成由内而外的温度梯度.研究表明,在900℃～1100℃沉积温度范围内,炭纤维表面最大沉积速率为64μm/h,比等温CVI的沉积速率 (0.1μm/h～0.25μm/h)快2个数量级以上.同时,分析并提出了该方法快速致密多孔预制体的机理.

CARBON-CARBON COMPOSITES PREPARED BY A RAPID DENSIFICATION PROCESS-CHEMICAL LIQUID-VAPOR INFILTRATION

Carbon-carbon comosites with density as high as 1.74g/cm3 were obtained within 3 hours by a novel method called chemical liquid-vapor infiltration densification (CLVD).The preforms adapted were carbon felt disks (160mm od×80mm id×10mm thick of each),which have been densified in a liquid carbon source.The liquid precursor used in the present work was composed of CYH and KEE.The disks were heated by radiation which could create an inside-out thermal gradient and immersed in liquid precursor in a water-cooled chamber.Rough-laminar and smooth-laminar deposited carbon microstructure was observed under crossed polarizers.The highest deposition rate obtained in this study was 64μm/h which was over two order of magnitude faster than the typical value of 0.1μm/h～0.25μm/h for the ICVI process in the temperature range from 900℃～1100℃.Also the reasons for rapid densification by this method were discussed considering a large thermal gradient within the preforms and chemical reaction occurred in liquid-vapor medium.