Li Ke, Kashkarov Egor, Ma Hailiang, Fan Ping, Zhang Qiaoli, Zhang Peng, Zhang Jilong, Wu Zhaohui, Wahl Larissa, Laptev Roman, Lider Andrey, Travitzky Nahum, Yuan Daqing
China Institute of Atomic Energy, Beijing 102413, China.
School of Nuclear Science and Engineering, National Research Tomsk Polytechnic University, 634050 Tomsk, Russia.
Materials (Basel). 2021 Nov 9;14(22):6737. doi: 10.3390/ma14226737.
This paper presents the results of microstructural analysis of novel preceramic paper-derived SiCf/SiC composites fabricated by spark plasma sintering. The sintering temperature and pressure were 2100/2200 °C and 60/100 MPa, respectively. The content of fibers in the composites was approx. 10 wt %. The SiC/SiC composites were analyzed by positron annihilation methods, X-ray diffraction technology, scanning electron microscopy, and Raman spectroscopy. Longer sintering time causes the proportion of the 6H-SiC composition to increase to ~80%. The increase in sintering temperature from 2100 °C to 2200 °C leads to partial transition of 4H-SiC to 6H-SiC during the sintering process, and the long-life component of positrons indicates the formation of Si vacancies. The Raman characteristic peaks of turbostratic graphite appear in the Raman spectrum of SiC fibers, this is caused by the diffusion of carbon from the surface of the SiC fiber and the preceramic paper during the high-temperature sintering process.
本文介绍了通过放电等离子烧结制备的新型陶瓷先驱体纸衍生SiCf/SiC复合材料的微观结构分析结果。烧结温度和压力分别为2100/2200℃和60/100MPa。复合材料中纤维的含量约为10wt%。采用正电子湮没方法、X射线衍射技术、扫描电子显微镜和拉曼光谱对SiC/SiC复合材料进行了分析。较长的烧结时间会使6H-SiC成分的比例增加到~80%。烧结温度从2100℃升高到2200℃会导致在烧结过程中4H-SiC部分转变为6H-SiC，并且正电子的长寿命成分表明形成了Si空位。在SiC纤维的拉曼光谱中出现了乱层石墨的拉曼特征峰，这是由于在高温烧结过程中碳从SiC纤维表面和陶瓷先驱体纸中扩散所致。
