( 1. 中南大學(xué) 粉末冶金國家重點(diǎn)實驗室， 長沙 410083;
2. 中南大學(xué) 機(jī)電工程學(xué)院， 長沙 410083)
摘 要: 以PAN基炭纖維（Cf）針刺整體氈為預(yù)制體，用化學(xué)氣相滲透(CVI)、浸漬炭化（IC）方法制備了不同炭纖維增強(qiáng)炭基體的多孔C/C坯體， 采用反應(yīng)熔滲（RMI）法制備C/C-SiC復(fù)合材料， 研究了滲Si前后坯體的密度和組織結(jié)構(gòu)。 結(jié)果表明：不同C/C坯體反應(yīng)溶滲硅后復(fù)合材料的物相組成為SiC相、 C相及單質(zhì)Si相； 密度低的坯體熔融滲硅后密度增加較多； 密度的增加與開口孔隙度并不是單調(diào)增加的關(guān)系， IC處理的坯體開口孔隙度低， 但滲硅后復(fù)合材料的密度增加較多； IC坯體中分布分散的樹脂C易與熔滲Si反應(yīng)， CVI坯體中的熱解C僅表層與熔滲Si反應(yīng)， 在Cf和SiC之間有熱解C 存在； 坯體密度相同時， IC處理的坯體中SiC量較多， 單質(zhì)Si相含量少且分散較好，而CVI坯體中SiC量較少， 單質(zhì)Si相的量較多； 制備方法相同時， 高密度的C/C坯體， 滲硅后C相較多。
關(guān)鍵字: C/CSiC復(fù)合材料； C/C坯體； 反應(yīng)熔滲Si； 顯微組織
（ 1. State Key Laboratory of Powder Metallurgy,
Central South University, Changsha 410083, China;
2. School of Mechanical and Electrical Engineering,
Central South University, Changsha 410083, China）
Abstract: C/C-SiC composites were fabricated by reactive melt infiltrating(RMI) Si to different C/C preforms prepared by chemical vapor infiltration(CVI) or resin impregnation and carbonization (IC). The changes of the density and microstructure of the preforms before or after infiltrating Si were studied. The results show that RMI C/C-SiC composites fabricated by infiltrating Si into different performs consist of SiC, C and residual Si phases. The lower the density of preform , the higher the densification of C/C-SiC composites after infiltrating Si is. But the increment of the density after infiltrating Si does not monotonely increase with the open porosity of preform. The density after infiltrating Si only increases more in preform fabricated by IC although its open porosity is lower.The resin carbon in preforms is easier to react with infiltrating Si , but pyrolytic carbon of on outer surface of the carbon fiber（Cf） reacts with infiltrating Si， leading to some pyrolytic carbon between Cf and SiC which protects Cf. The amount of each phase in the composites is related to the type of carbon and the density of C/C preforms. At same density of preforms， the amount of SiC is more, and the amount of residual Si is litter and distribution of Si is more dispersive in the composites prepared by IC than that by CVI after infiltrating Si.
Key words: C/C-SiC composites；C/C preform；reactive melt infiltrating Si； microstructure
