无机材料学报

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真空气氛下非晶硅碳氮(SiCN)陶瓷的高温晶化行为

夏 熠, 乔生儒, 王强强, 张程煜, 韩 栋, 李 玫   

  1. 西北工业大学 超高温结构复合材料实验室, 西安 710072
  • 收稿日期:2008-10-23 修回日期:2008-12-25 出版日期:2009-07-20 网络出版日期:2009-07-20

Crystallization of Amorphous SiCN Ceramic Annealed in Vacuum

XIA Yi, QIAO Sheng-Ru, WANG Qiang-Qiang, ZHANG Cheng-Yu, HAN Dong, LI Mei   

  1. National Key Laboratory of Thermostructure Composite Materials, Northwestern Polytechnical University, Xi’an 710072, China
  • Received:2008-10-23 Revised:2008-12-25 Published:2009-07-20 Online:2009-07-20

摘要: 以六甲基二硅氮烷为单一前驱体,采用电热裂解化学气相沉积技术制备了SiCN陶瓷. 借助X射线衍射仪、透射电子显微镜研究了真空环境中非晶SiCN陶瓷在1300~1900℃范围内的晶化行为,并根据研究结果,运用分解-结晶机理解释了其晶化过程. 非晶SiCN陶瓷在低于1300℃开始发生分解,形成富Si-C区域,并最终发生β-SiC结晶. 其结晶度随热处理温度的升高而愈加明显.在1700℃处理时发生β-SiC→α-SiC相变. 分解形成的N-难以与Si-结合形成富Si-N区域,最终以N2形式溢出,在整个热处理温度范围没有出现氮气下热处理时存在的Si3N4结晶.

关键词: 非晶SiCN陶瓷, 晶化行为, 相变, 显微结构

Abstract: SiCN ceramic was fabricated by electro-thermal pyrolysis using hexamethyldisilazane as precursor. X-ray diffraction and transmission electron microscope were employed to study crystallization process of amorphous SiCN after annealing at temperature from 1700℃ to 1900℃ in vacuum. Decomposition-crystallization mechanism was used to characterize its crystallization process. Amorphous SiCN begin to decompose below 1300℃ in vacuum and Si-C-enriched districts are formed and then changes to form β-SiC crystal. Crystallinity degree increases as treated temperature rises. Phase transition from β-SiC to α-SiC occurs after annealing at 1700℃. The nitrogen is released in the form of N2 and Si3N4 crystal is not detected though it often exists in the SiCN annealed in N2 atmosphere.

Key words: amorphous SiCN, crystallization, phase transition, microstructure

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