耦合物理场CVI快速增密C/C复合材料及动力学探讨  

PREPARING C/C COMPOSITES BY CVI WITH MULTI-FACTOR COUPLING PHYSICAL FIELDS AND DISCUSSING THE DYNAMIC PROCESS

作　　者：谢志勇[1] 黄启忠[1] 苏哲安[1] 张明瑜[1] 梁锦华[1] 黄伯云[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《复合材料学报》2005年第4期47-52,共6页Acta Materiae Compositae Sinica

基　　金：国家重点基础研究发展计划-973计划(2006CB600901);中南大学研究生创新工程项目(博士论题创新[2003]30614)

摘　　要：采用多元耦合物理场CVI工艺,用炭毡作为增强体,在增强体中设计导电层,产生温度场和电磁场梯度,在自行设计的CVI炉中增密C/C复合材料,对温度、系统压力和气体流量等工艺进行了优化;采用偏光显微镜研究了热解炭的显微结构;用X射线衍射研究了材料的石墨化度;探讨了本工艺中的有内热源和无内热源的二元传热机制,多元耦合物理场的有机耦合对“消耗传质”的抑制作用,以及电磁场对沉积的影响和3种典型的生长模型。研究表明,多元耦合物理场CVI增密速度快,初始密度为0.2g/cm3,尺寸为260mm×60mm×20mm的增强体,在920℃、4kPa条件下沉积20h,试样可增密到1.71g/cm3;可获得粗糙层结构(RL)、光滑层结构(SL)、带状结构(Bandedstructure)等热解炭的结构,在960℃、0.1kPa条件下可获得较高织构的粗糙层结构。Installing special electric layer in preforms of carbon felt, C/C composites were fabricated by chemical vapor infiltration （CVI） with multi-factor coupling physical fields, and the infiltration conditions were optimized.The textures of pyrolytic carbons were observed using polarized light microscopy （PLM）, and the graphitization degree of these C/C composites was analyzed by XRD; The effect of electromagnetic field on the CVI and dynamic process of dual convective heat of outer thermogenesis and inner thermogenesis and mass restrainning of consuming transfer, and three of deposition models were discussed. The results show that the rate of deposition of pyrolytic carbon is improved with multi-factor coupling physical fields, and the porous carbon-carbon preforms （260 mm ×60 mm×20 mm） can be densified in one-cycle. C/C composites with density of more than 1.7 g/cm^3 are obtained within 20 h. Though optimizing the infiltration conditions, some kinds of microstructure of pyrolytic carbons can be obtained, ranging from rough laminar, smooth laminar, isotropic and banded structure. Under the infiltration conditions of 960℃ and 0. 1 kPa, the rough laminar of higher texture can be obtained.

关 键 词：多元耦合物理场CVI C/C复合材料 快速致密 传质传热 沉积模型 

分 类 号：TB332[一般工业技术—材料科学与工程]