(中南大學(xué) 粉末冶金國家重點(diǎn)實(shí)驗(yàn)室，長沙 410083)
摘 要: 為了改善C/C-ZrC-SiC復(fù)合材料的燒蝕性能，采用反應(yīng)熔滲法(RMI)在1850 ℃制得一種新型耗散防熱FexSiy改性C/C-ZrC-SiC復(fù)合材料，并研究熔滲母料中Fe含量的變化對該復(fù)合材料顯微結(jié)構(gòu)和燒蝕性能的影響。結(jié)果表明：隨著熔滲母料中Fe含量的升高，復(fù)合材料的密度呈現(xiàn)先降低后增加的趨勢。當(dāng)Fe含量超過6%(摩爾分?jǐn)?shù))時(shí)，沿垂直無緯布方向，復(fù)合材料中出現(xiàn)獨(dú)立于SiC和ZrC之間的FexSiyC固溶相，其相含量隨Fe含量的升高而增多；沿平行無緯布方向，復(fù)合材料中發(fā)現(xiàn)眾多以灰色FexSiyC相間隔的“團(tuán)粒型”排布的ZrC相，其粒徑約為10 μm。通過對不同F(xiàn)e含量的FexSiy改性C/C-ZrC-SiC復(fù)合材料燒蝕性能進(jìn)行表征，結(jié)果表明，當(dāng)Fe含量為8.5%(摩爾分?jǐn)?shù))時(shí)，F(xiàn)exSiy改性C/C-ZrC-SiC復(fù)合材料的燒蝕性能最佳，質(zhì)量燒蝕率和線燒蝕率分別為2.3×10-3 g/s和0.7×10-3 mm/s，相比純C/C-ZrC-SiC復(fù)合材料分別降低3.6×10-3 g/s和3.61×10-3 mm/s。其優(yōu)異的抗燒蝕性能主要得益于低熔FexSiy相的耗氧耗熱和SiO2熔體補(bǔ)償，促使樣品表面形成一層致密、低氧透過率的富SiO2層，避免基體的進(jìn)一步燒蝕。
關(guān)鍵字: C/C-ZrC-SiC復(fù)合材料；反應(yīng)熔滲法；FexSiy；顯微結(jié)構(gòu)；燒蝕性能
（State Key laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:To improve the ablation performance of C/C-ZrC-SiC composites, a new type of dissipative heat-proof FexSiy modified C/C-ZrC-SiC composites was prepared by the reactive infiltration method (RMI) at 1850 ℃, and the effect of Fe content in the infiltration masterbatch on the microstructure and ablation properties was studied. The results indicate that, with the increase of Fe content, the density of the composites first decreases and then increases. When the Fe content exceeds 6% (mole fraction), the FexSiyC solid solution phase independent of SiC and ZrC appears in the vertical weft free direction, and the phase content increases with the increase of Fe content along the parallel weft free direction, many “granular” ZrC phases separated by gray FexSiyC are found in the composites, and the particle size is about 10 μm. The ablative properties of FexSiy modified C/C-ZrC-SiC composites with different Fe content were characterized. The results show that the ablative properties of FexSiy modified C/C-ZrC-SiC composites are the best when the Fe content is 8.5% (mole fraction), and the mass ablative rate and linear ablative rate are 2.3×10-3 g/s and 0.7×10-3 mm/s, respectively. Compared with the pure C/C-ZrC-SiC composites, the ablation rate was reduced by 3.6×10-3 g/s and 3.61×10-3 mm/s, respectively. Its excellent ablation resistance is mainly due to the oxygen and heat consumption of low melting FexSiy phase and the compensation of SiO2 melt, which promotes the formation of a dense SiO2 rich layer with low oxygen permeability on the surface of the sample to avoid further ablation of the matrix.
Key words: C/C-ZrC-SiC composites; reactive infiltration method; FexSiy; microstructure; ablation performance
