定向碳纳米管/炭纳米复合材料形貌和显微结构  

Microstructure of the pyrocarbon in aligned carbon nanotube/carbon composites

作　　者：李志[1,2] 巩前明[1,2,3] 王野[1,2] 吴建军[1,2] 梁吉[1,2] 黄启忠[4] 熊翔[4] 黄伯云[4] 

机构地区：[1]清华大学机械系,北京100084 [2]清华大学先进成形制造教育部重点实验室,北京100084 [3]Department of Materials Science and Engineering,Cornell University,Ithaca [4]中南大学粉末冶金国家重点实验室,湖南长沙410083

出　　处：《新型炭材料》2010年第5期335-342,共8页New Carbon Materials

基　　金：先进成形教育部重点实验室基金(2008010);航空预研基金(2006273)~~

摘　　要：以CVD法定向碳纳米管(ACNTs)阵列为骨架,利用化学气相渗透(CVI)工艺制备了新型定向碳纳米管/炭(ACNT/C)纳米复合材料。通过偏光金相显微镜(PLM)、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)、X射线衍射(XRD)和Raman光谱等分析方法对其显微结构和热解炭沉积机理进行了研究。结果表明:所制ACNT/C纳米复合材料的热解炭结构主要为类粗糙层结构,围绕碳纳米管生长的热解炭石墨层片结构清晰,并且碳纳米管和热解炭之间具有良好的界面结合;而在相同工艺条件下围绕炭纤维生长的热解炭为典型的光滑层结构。这可能是由于在热解炭沉积过程中存在碳纳米管"诱导"沉积过程,即沿着碳纳米管径向的离域化共轭π键和具有类似结构的芳香族大分子通过π-π非共价键作用相结合,并在CNTs纳米尺寸的影响下,芳香族大分子按照"软取向"(Softepitaxy)围绕碳纳米管生成环形层片状类石墨结构的热解炭。该研究结果有望为热解炭的可控沉积起到一定的借鉴作用。Aligned carbon nanotube reinforced carbon matrix（ACNT/C）composites were fabricated by densifying an ACNT preform with chemical vapor infiltration（CVI）and their microstructure was investigated by XRD,SEM,HRTEM,polarized light microscopy and Raman spectroscopy.Results show that the pyrocarbon in ACNT/C composites was of mainly rough lamella type,while that in traditional carbon/carbon composites obtained using the same process was of typically smooth lamella type with a larger interlayer spacing and a smaller layer stack height.Pyrocarbon around CNTs shows a clear annular graphitic-layered microstructure with good interfacial bonding between CNTs and pyrocarbon.This might be ascribed to the intermolecular interaction between CNTs and aromatic molecules,i.e.,CNTs have abundant radial delocalized conjugated π-π electrons,which can attract polynuclear aromatic molecules with a similar structure through van der Waals forces.These polynuclear aromatic molecules are therefore oriented around the CNT outer surface under a ＂soft epitaxy＂ mechanism.In contrast,carbon fibers composed of turbostratic carbon have no such effect during CVI.

关 键 词：定向碳纳米管 炭/炭 热解炭 纳米复合材料 微观结构 

分 类 号：TB383.1[一般工业技术—材料科学与工程]