纸叠层设计制备SiC/Si层状陶瓷研究

Study on SiC/Si laminated ceramics fabricated from paper by laminated design

针对层状陶瓷复合材料制备工艺复杂且制备成本高的不足,提出了一种无需预先成型基片,且在常压烧结工艺下制备层状陶瓷复合材料的新工艺.采用原位反应法,以纸为原料,通过叠层设计、低温碳化和高温渗硅反应制备了具有层状结构特征的SiC/Si陶瓷复合材料.并采用XRD、EDS和显微镜对材料的组成和微观结构进行分析.结果表明,叠层纸碳化后成为含有层状结构特征的碳骨架,渗硅后得到的SiC层与Si层交替排列的具有明显层状结构特征的SiC/Si层状陶瓷复合材料.并揭示了叠层纸制备SiC/Si层状陶瓷复合材料中Si/C界面的反应机理,Si/C界面的反应是一个扩散反应的过程.

To resolve the problems of high production cost and fabrication process complexity of laminated ceramic composites, a new technology to fabricate laminated ceramic composites was developed using pressureless-sintering without the need for pre-shaping of the laminates. Using in-situ reaction, SiC/Si laminated ceramic composites were fabricated by paper lamination, carbonization at low temperature and reaction with melt silicon at high temperature with conventional paper as raw material. The phase composition and microstructure of the specimens were analyzed by XRD, EDS and microscope. The results showed that the specimen after carbonization is carbon walls with laminated pore structure, and the final product possesses laminated structruce aligned with βSiC layer and silicon layer alternatively. The reaction mechanism of silicon-carbon interface in laminated SiC/Si ceramics was discovered, and the process of silicon-carbon interface reaction was found to be a reaction-diffusion process.