【超高温陶瓷基复合材料】预制坯孔结构的影响

Reaction mechanism and microstructure development of ZrSi₂ melt-infiltrated C_f/SiC-ZrC-ZrB₂ composites: The influence of preform pore structures

ZrSi₂ 熔体渗透C_f/SiC-ZrC-ZrB₂复合材料的反应机理及微观结构：预制坯孔结构的影响

 Authors: Xiaowu Chen, Dewei Ni*, Yanmei Kan, Youlin Jiang, Haijun Zhou, Zhen Wang and Shaoming Dong**

Volume 4, Issue 3, Pages 266-275

Reactive melt infiltration (RMI) is an effective method for fabrication of highly dense carbon fiber reinforced ultra-high temperature ceramic matrix composites (C_f/UHTCs). 

反应熔体渗透（RMI）是制造高密度碳纤维增强超高温陶瓷基复合材料（C_f/UHTCs）的有效方法。

In this work, C_f/SiC-ZrC-ZrB₂ composites were fabricated by infiltrating ZrSi₂ melt into porous C_f/B₄C-C preforms, where the physical and chemical reactions involved during the RMI process were identified and analyzed. 

在本工作中，通过将ZrSi₂熔体渗透到多孔C_f/B₄C-C预制件中制备C_f/SiC-ZrC-ZrB₂复合材料

Inhomogeneous infiltration between the inter- and intra-bundle pores was revealed, and was found to be strongly related to the pore structures of the C_f/B₄C-C preform. 

确定并分析了RMI过程中所涉及的物理和化学反应。发现了束间和束内孔隙之间的不均匀渗透，并且发现其与C_f/B₄C-C预制件的孔结构密切相关。

It is indicated that the inhomogeneous infiltration can be mitigated remarkably with increasing porosity and pore size of the preform. 

结果表明，随着预制件孔隙率和孔径的增加，可以显著减轻非均匀渗透。

The effect of pore size on the RMI process was also investigated by a quantitative model, which agrees very well with the experiment results. 

进而通过定量模型研究了孔径对RMI过程的影响，该模型与实验结果非常吻合。

It further indicates that the inhomogeneous infiltration can also be relieved at elevated RMI temperature. 

该结果进一步表明，在较高的RMI温度，非均匀渗透也可以得到缓解。

However, excessive infiltration at elevated temperature or more porous preform may cause serious erosion on interphase and fibers, leading to mechanical properties deterioration of the final composites.

然而，在高温下过度渗透或具有更多孔的预制件可能导致中间相和纤维的严重侵蚀，导致最终复合材料的机械性能劣化。

文中部分图片：

制备方法

Fig. 2. Schematic diagram of the RMI apparatus (a) and the heating curve during the RMI process (b).

多孔预制体分析

Fig. 3. Characterizations of the porous C_f/B₄C-C preforms: (a) pore size distribution, (b) pore parameters, (c–d) XRD patterns of the C_f/B₄C-C preforms and the RMI-composites.

预制体和反应熔渗法制备的复合材料的微观形貌

Fig. 4. SEM images of cross-sections of the C_f/B₄C-C preforms and the RMI-composites: (a–c) Pre-1, Pre-2, Pre-3 and (d–i) Com-1, Com-2, Com-3.

孔径对渗透的影响

Fig. 6. Schematic diagram of reaction layer growth during RMI (a) and the variation of pore radius with infiltration time.

制备温度对熔渗的影响

Fig. 9. Contact angle of ZrSi₂ melt/reaction layer at various temperatures.

抗弯强度

Fig. 11. Three-point bending test of the composites (Com-2 and Com-3): (a) Schematic diagram of the test, (b) bending load-displacement curves and (c–d) SEM images of the fracture surfaces.

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董绍明研究员和倪德伟副研究员带领的科研团队果然实力非凡，通过理论和实验相结合阐明了预制坯孔结构对反应熔渗法制备陶瓷基复合材料的反应机理和材料性能的影响。

Xiaowu Chen is a graduate student in Shanghai Institute of Ceramics, University of Chinese Academy of Sciences. He focuses his researches on the fabrication and performance optimization of ultra-high temperature ceramics matrix composites.

Dewei Ni is an associate professor of Shanghai Institute of Ceramics, Chinese Academy of Sciences. He received his B.S. in 2006 from the Department of Materials Science and Engineering, Sichuan University, and his Ph.D. in 2011 from Graduate School of the Chinese Academy of Sciences. After that, he joined Technical University of Denmark starting as a postdoctoral researcher and developed as an independent researcher in 2013. At the beginning of 2016, he moved back to Shanghai Institute of Ceramics, Chinese Academy of Sciences as an associate professor under the support of CAS Pioneer Hundred Talents Program. His current research interests are centered on development and understand the relationship among the fabrication, properties and hierarchical structures of ultra-high temperature ceramics matrix composites.

Shaoming Dong is a professor of Shanghai Institute of Ceramics, Chinese Academy of Sciences. He received his bachelor's and master's degree from South China University of Technology in 1984 and 1987 respectively. In 1996, he received his Ph.D from Shanghai Institute of Ceramics, Chinese Academy of Sciences. From 1998 to 1999 he visited the Thermal Composite Materials Laboratory of the University of Bordeaux, France. From 1999 to 2002, he was a Visiting Fellow at Advanced Energy Research Institute, Kyoto University, Japan. He is engaged in basic research, application and development of advanced structural ceramics and composite materials.