Effects of infiltration conditions on the densification behavior of carbon/carbon composites prepared by a directional-flow thermal gradient CVI process
✍ Scribed by Zhong-hua Tang; Dian-ning Qu; Jie Xiong; Zhi-qiang Zou
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 275 KB
- Volume
- 41
- Category
- Article
- ISSN
- 0008-6223
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✦ Synopsis
Multiple quasi three-dimensioned carbon fibre preforms with disk-like shape were simultaneously densified by a directional flow thermal gradient CVI process. The effects of infiltration conditions, including temperature (ranging from 850 to 1050 8C), temperature gradient (5 and 10 8C / mm), pressure (2.5, 5.0, 7.5 and 9.5 kPa) and the type of carrier gas (N or 2 H ), on the densification behavior of the resultant carbon / carbon composites were investigated. The results showed that 2 lower temperatures (below 900 8C), a larger temperature gradient and higher pressure are favorable for higher average bulk 3 density and homogeneous infiltration. Carbon / carbon composites disks with an average bulk density of 1.78 g / cm were achieved in one CVI cycle at a total pressure of 9.5 kPa. It was also found that adding N carrier gas has no pronounced 2 influence on the densification of the preforms. As compared to N , H had positive effects on the densification of the 2 2 preforms for temperatures above 900 8C, but it had negative effects on the densification when the control temperature was as low as 850 8C.