(国防科学技术大学 新型陶瓷纤维及其复合材料国家重点实验室，长沙 410073)
摘 要: 采用碳纳米管改善纤维与基体间的界面结合，同时利用碳纳米管自身的优异性能对碳化硅纤维增强碳化硅复合材料(SiCf/SiC)进行二次增强。通过化学气相沉积工艺(CVD)在SiC纤维编织件内原位生长碳纳米管，优化碳纳米管原位生长过程中的碳源流量、反应温度和反应时间等工艺参数，对碳纳米管的原位生长工艺及机理进行系统分析，并结合先驱体浸渍裂解工艺(PIP)制备CNTs-SiCf/SiC复合材料，探讨原位生长碳纳米管的引入对复合材料力学性能的影响。结果表明，优化后的工艺参数如下：反应温度750 ℃，C2H2、H2和N2流量比1/1/3，C2H2流量100~150 mL/min，反应时间60 min；碳纳米管的引入使SiCf/SiC复合材料的弯曲强度、弯曲模量和断裂韧性分别提高了16.3%、90.4%和106.3%。
关键字: SiCf/SiC复合材料；碳纳米管；化学气相沉积；原位生长；浸渍；裂解
SiCf/SiC composites
（State Key Laboratory of Advanced Ceramic Fibers and Composites,
National University of Defense Technology, Changsha 410073, China）
Abstract:Carbon nanotubes (CNTs) were incorporated in the matrices to change the surface microstructure of SiC fiber and ameliorate the interfacial bonding between SiC fiber and SiC matrix, as well as acting as a bridge to secondly reinforce SiCf/SiC composites. CNTs-SiCf/SiC composites were successfully fabricated by in-situ growing CNTs directly in the composite performs via a chemical vapor deposition(CVD) process followed by polymer impregnation and pyrolysis (PIP) routes densification. The effects of carbon resource (C2H2) flux, reaction temperature and reaction time on properties of CNTs were studied, the technics and growth mechanism of CNTs were investigated. Finally the effect of in-situ grown CNTs introduction on the mechanical properties of the CNTs-SiCf/SiC composite was discussed. The results indicate that optimized parameters for CNTs growing are as follows: reaction temperature 750 ℃, reaction time 60 min, flux ratio of C2H2 to H2 to N2 1/1/3 and C2H2 flux 100−150 mL/min. As a result of the introduction of CNTs, flexural strength, flexural modulus and fracture toughness of SiCf/SiC composites are increased by 16.3%, 90.4% and 106.3%, respectively.
Key words: SiCf/SiC composites; carbon nanotubes; chemical vapor deposition; in-situ growth; impregnation; pyrolysis
