(國(guó)防科學(xué)技術(shù)大學(xué) 新型陶瓷纖維及其復(fù)合材料國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410073)
摘 要: 采用碳納米管改善纖維與基體間的界面結(jié)合，同時(shí)利用碳納米管自身的優(yōu)異性能對(duì)碳化硅纖維增強(qiáng)碳化硅復(fù)合材料(SiCf/SiC)進(jìn)行二次增強(qiáng)。通過(guò)化學(xué)氣相沉積工藝(CVD)在SiC纖維編織件內(nèi)原位生長(zhǎng)碳納米管，優(yōu)化碳納米管原位生長(zhǎng)過(guò)程中的碳源流量、反應(yīng)溫度和反應(yīng)時(shí)間等工藝參數(shù)，對(duì)碳納米管的原位生長(zhǎng)工藝及機(jī)理進(jìn)行系統(tǒng)分析，并結(jié)合先驅(qū)體浸漬裂解工藝(PIP)制備CNTs-SiCf/SiC復(fù)合材料，探討原位生長(zhǎng)碳納米管的引入對(duì)復(fù)合材料力學(xué)性能的影響。結(jié)果表明，優(yōu)化后的工藝參數(shù)如下：反應(yīng)溫度750 ℃，C2H2、H2和N2流量比1/1/3，C2H2流量100~150 mL/min，反應(yīng)時(shí)間60 min；碳納米管的引入使SiCf/SiC復(fù)合材料的彎曲強(qiáng)度、彎曲模量和斷裂韌性分別提高了16.3%、90.4%和106.3%。
關(guān)鍵字: SiCf/SiC復(fù)合材料；碳納米管；化學(xué)氣相沉積；原位生長(zhǎng)；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
