(國防科學技術大學 新型陶瓷纖維及其復合材料國家重點實驗室，長沙 410073)
摘 要: 采用碳納米管改善纖維與基體間的界面結合，同時利用碳納米管自身的優(yōu)異性能對碳化硅纖維增強碳化硅復合材料(SiCf/SiC)進行二次增強。通過化學氣相沉積工藝(CVD)在SiC纖維編織件內原位生長碳納米管，優(yōu)化碳納米管原位生長過程中的碳源流量、反應溫度和反應時間等工藝參數，對碳納米管的原位生長工藝及機理進行系統(tǒng)分析，并結合先驅體浸漬裂解工藝(PIP)制備CNTs-SiCf/SiC復合材料，探討原位生長碳納米管的引入對復合材料力學性能的影響。結果表明，優(yōu)化后的工藝參數如下：反應溫度750 ℃，C2H2、H2和N2流量比1/1/3，C2H2流量100~150 mL/min，反應時間60 min；碳納米管的引入使SiCf/SiC復合材料的彎曲強度、彎曲模量和斷裂韌性分別提高了16.3%、90.4%和106.3%。
關鍵字: SiCf/SiC復合材料；碳納米管；化學氣相沉積；原位生長；浸漬；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
