文章信息/Info

Title:

Microstructure and Oxidation Resistance of C/C-SiC Composites Prepared by Reactive Melt Infiltration

作者:

劉躍; 付前剛; 李賀軍; 李關美

西北工業大學 超高溫結構復合材料重點實驗室 陜西省碳/碳復合材料工程技術研究中心

Author(s):

LIU Yue;  FU Qiangang;  LI Hejun;  LI Guanmei

Science and Technology on Thermostructural Composite Materials Laboratory, Northwestern Polytechnical University

關鍵詞:

C/C-SiC復合材料; 反應熔滲; 抗氧化性能; 抗熱震性能

DOI:

10.7502/j.issn.1674-3962.2016.02.06

文獻標志碼:

A

摘要:

采用反應熔滲法 (RMI) 制備了C/C�睸iC復合材料，對比研究了不同密度C/C預制體所制備C/C�睸iC復合材料在1 500 ℃靜態空氣環境中抗氧化性能和1 500 ℃�苁覝乜篃嵴鹦阅埽�借助X射線衍射分析儀 (XRD) 與掃描電子顯微鏡 (SEM) 對C/C�睸iC復合材料的相組成及微觀形貌進行了分析。結果表明，密度為1.0 g/cm3的C/C復合材料孔徑分布在10~100  μm范圍，有利于液相Si的滲入，進而可獲得高致密度的C/C�睸iC復合材料；而密度為1.7 g/cm3的C/C復合材料因孔徑太小(<10  μm)，不利于Si熔體的滲入，僅能在C/C復合材料表面形成SiC涂層。由于C/C復合材料與SiC的熱膨脹系數不同，在氧化和熱震試驗過程易造成SiC涂層開裂，致使用密度為1.7 g/cm3的C/C預制體制備的C/C�睸iC復合材料抗氧化與抗熱震性能下降。而密度為1.0 g/cm3的C/C預制體制備的復合材料內部致密的SiC基體與低密度C/C復合材料形成鑲嵌界面，有效緩解熱膨脹系數不匹配而造成的缺陷，從而具有優異的抗氧化和抗熱震性能。

Abstract:

In this study, two different densities of carbon/carbon (C/C) composites modified by SiC were prepared using reactive melt infiltration method (RMI). The phase composition, microstructure and element distribution of the as�瞤repared composites were characterized by X�瞨ay diffraction (XRD) and scanning electron microscope (SEM). The oxidation resistance and thermal shock resistance of C/C�睸iC composites were investigated, and the morphology changes of the C/C�睸iC composites after oxidation test and thermal shock test were observed by SEM. The results show that the sizes of pores determined the infiltrating depth of the molten Si during RMI. The C/C1.0�睸iC composites had a low initial density with large sizes (10~100  μm), which was beneficial to infiltration of the molten melts and improvement of the final density. The oxidation behavior and thermal shock of C/C�睸iC composites were measured at 1500 ℃ in statics air. It indicated that C/C1.7�睸iC composites had a poor oxidation resistance and thermal shock resistance due to the coefficient of thermal expansion mismatch of SiC coating and C/C substrate. The mismatch would result in cracking or peeling and even failure of the coating. Nevertheless, C/C1.0�睸iC composites had a good oxidation resistance and thermal shock resistance because of the existence of multilayer interface between SiC matrix and C/C substrate, which effectively relieved the coefficient of thermal expansion mismatch of SiC matrix and C/C substrate. Therefore, the oxidation resistance and thermal shock resistance of C/C1.0�睸iC composites were improved significantly.