用CVI增密技术制备航空刹车用C/C复合材料
来源期刊：中南大学学报(自然科学版)2002年第4期
论文作者：汤中华 邹志强 熊杰 徐惠娟
文章页码：380 - 384
关键词：预制体;热梯度CVI; C/C复合材料;粗糙层结构
Key words：preform; thermal gradient CVI; carbon/carbon composites; rough laminar microstructure
摘 要：以炭布与炭纤维薄毡交替成叠层,采用针刺技术在垂直布面方向引入增强纤维,制成准三维预制体,在自行研制的热梯度CVI炉中制备了航空刹车用C/C复合材料;采用偏光显微镜研究了沉积炭的显微结构.研究结果表明:该CVI炉可实现多试样同时沉积,且位于料柱不同位置的试样密度分布较均匀;对外径为110 mm,内径为45 mm,厚度为15~20 mm的试样,在80 h内,试样的平均密度可达1.60 g/cm3,炭的有效利用率可达27%;在料柱的不同位置以及同一试样中沿径向的不同位置,沉积炭的显微结构都有所不同;沉积炭的显微结构有粗糙层结构、带状结构以及光滑层结构;通过工艺参数的优化,可以得到以粗糙层结构为主的C/C复合材料.
Abstract: The carbon cloth and carbon fiber felt are laminated alternately and then needled to prepare the porous carbon/carbon preforms, from which the carbon/carbon composites for aircraft brakes are fabricated by the thermal gradient CVI process. Furthermore, the microstructure of the material is studied by polarized light microscopy. The results show that the process allows simultaneous infiltration of multi to preformper run. Porous carbon-carbon preforms, 110 mm×45 mm×(15~20) mm can be densified in a one-cycle. Uniform carbon-carbon disks with the average density of more than 1.60 g/cm3 are obtained in 80 h. The precursor utilization efficiency can be as high as 27%. It is also found that the microstructure of pyrocarbon matrix varies from rough laminar structure to banded structure to smooth laminar structure along the radial of the disk. And it alsovaries along the height of the disk column. Through optimizing the infiltration conditions, carbon-carbon composites in which the rough laminar microstructure predominates can be obtained.
