(1. 中南大學 粉末冶金國家重點實驗室，長沙 410083;
2. 中南大學 化學化工學院，長沙 410083)
摘 要: 采用自行設(shè)計的多元耦合物理場CVI爐增密炭/炭(C/C)復合材料，用炭氈作為纖維增強體，在坯體內(nèi)部設(shè)計特殊的導電發(fā)熱層，使坯體內(nèi)部的溫度場、氣體反應的中間產(chǎn)物濃度場、電磁場等多元物理場實現(xiàn)耦合，實現(xiàn)坯體的快速增密。采用偏光顯微鏡研究沉積熱解炭的組織結(jié)構(gòu)；用X射線衍射儀研究C/C復合材料的石墨化度和微晶尺寸；用掃描電鏡觀察材料斷口和熱解炭沉積表面的形貌；并對CVI熱解炭的生長方式進行研究。研究表明：獲得SL、RL和帶狀等多種熱解炭結(jié)構(gòu)；不同的結(jié)構(gòu)具有不同的形貌特征，其中SL的斷口平整，RL的斷口呈溝槽構(gòu)造；并提出前者為小分子平滑生長模型、后者為大分子錐狀生長模型。
關(guān)鍵字: 多元耦合物理場CVI；炭/炭復合材料；微觀結(jié)構(gòu)；生長模型
chemical vapor infiltration
（1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083,China;
2. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China）
Abstract:Using carbon felt as porous performs, installing special electric layer in the performs forming the grads of temperature and electromagnetism, C/C composites were fabricated by chemical vapor infiltration (CVI) in multi-factor coupling physical fields. The textural of pyrolytic carbons were observed by polarized light microscopy(PLM), and the graphitization degree and microcrystal size of these C/C composites was analyzed by XRD. The micromorphology of fracture and deposition surface was observed by SEM. At last, two kinds of growth mode of pyrolytic carbon were put forward. The results show that rough laminar, smooth laminar and banded structure can be obtained, and their micromorphology, graphitization degree and microcrystal size exist different; The fracture appearance of SL is very flat and smooth, but that of RL is rough and more groove exists. The former is deposited by smoothness growth model of smaller molecule, the latter by taper growth model of bigger molecule.
Key words: multi-factor coupling physical fields CVI; carbon/carbon composites; microstructure; growth model
