煤油蒸气为前驱体热梯度CVI法制备C/C复合材料  

Preparation of C/C composites by thermal gradient chemical vapor infiltration with vaporized kerosene as a precursor

作　　者：张永辉[1] 王继平[1] 金志浩[1] 

机构地区：[1]西安交通大学金属材料强度国家重点实验室,陕西西安710049

出　　处：《新型炭材料》2010年第2期141-145,共5页New Carbon Materials

基　　金：国家自然科学基金(50272051)~~

摘　　要：以炭毡为预制体,煤油蒸气为前驱体,利用两个热源分别加热预制体的上下表面,形成两个热梯度和双沉积面,第三个热源加热前驱体保证反应气体的供给,采用这种改进的化学液相气化渗入法快速制备了炭/炭(C/C)复合材料。对C/C复合材料的密度和气孔率进行了表征,并通过XRD,SEM等方法对其石墨化程度、显微结构进行了研究。结果表明:C/C复合材料的密度随沉积温度的升高呈线性增加,而气孔率逐渐减小,体积密度为0.2g/cm3的预制体在1100℃沉积3h后密度达到1.72g/cm3。2200℃热处理后,C/C复合材料的d002显著降低,具有较高的石墨化程度。C/C复合材料中的炭纤维被环状的热解炭所包围。沉积过程中前驱体较短的对流和扩散路径以及预制体中存在的上下热梯度和相应的双沉积面是材料快速制备的主要因素。A thermal gradient chemical vapor infiltration method with vaporized kerosene as a precursor for the fabrication of C/C composites was studied, in which a disc-shaped carbon felt preform was sandwiched within two flat heating sources, forming a temperature gradient, and the precursor was supplied with a third heating source. The density and open porosity of the composites were investigated by the Archimedes method （in water） and microstructures were studied by SEM. Results shows that the densities of the composites increase linearly with temperature and the C/C composite has a density up to 1.72 g/cm^3 when a carbon felt with a bulk density of 0.2 g/cm3 was infiltrated at 1 100 ℃ for 3 h.. The interlayer spacing （ d002 ） decreases and the composite can be easily graphitized at 2 200 ℃. The carbon fibers in the composites are surrounded by a ring of pyrocarbon. The deposition process is analyzed by dividing the reactor into four regions associated with different functions. The rapid densification can be accounted for by the short convection and diffusion paths for the precursor and the thermal gradients across the preform.

关 键 词：炭/炭复合材料 化学液相气化渗入法 快速制备 

分 类 号：TB332[一般工业技术—材料科学与工程]