X-ray Tomographic Study of Chemical Vapor Infiltration Processing of Ceramic Composites
X-ray Tomographic Study of Chemical Vapor Infiltration Processing of Ceramic Composites
复制标题
DOI：
10.1126/science.260.5109.789
复制
发表时间：
1993-05
期刊：
影响因子：
56.9
通讯作者：
J. Kinney;T. Breunig;T. Starr;D. Haupt;M. C. Nichols;S. Stock;M. D. Butts;R. Saroyan
中科院分区：
文献类型：
--
作者：
J. Kinney;T. Breunig;T. Starr;D. Haupt;M. C. Nichols;S. Stock;M. D. Butts;R. Saroyan
改进的陶瓷基复合材料的制造将需要更好地理解工艺变量以及它们如何控制复合材料微观结构的发展。非侵入性的，高分辨率的X射线断层扫描方法已被用来测量碳化硅的生长在编织尼龙纤维复合材料在化学气相渗透。高空间分辨率允许测量单个纤维束内的致密化，并原位跟踪宏观孔的闭合。实验提供了一个直接测试最近提出的模型，描述了如何在渗透过程中的表面积可用于基质沉积的变化。测量结果表明，该表面积是独立的纤维结构和位置内的预制件，并在复合材料固结的最后阶段由大规模的大孔隙率为主。测量的表面积与理论模型吻合得很好。
The fabrication of improved ceramic-matrix composites will require a better understanding of processing variables and how they control the development of the composite microstructure. Noninvasive, high-resolution methods of x-ray tomography have been used to measure the growth of silicon carbide in a woven Nicalon-fiber composite during chemical vapor infiltration. The high spatial resolution allows one to measure the densification within individual fiber tows and to follow the closure of macroscopic pores in situ. The experiments provide a direct test of a recently proposed model that describes how the surface area available for matrix deposition changes during infiltration. The measurements indicate that this surface area is independent of the fiber architecture and location within the preform and is dominated by large-scale macroporosity during the final stages of composite consolidation. The measured surface areas are in good agreement with the theoretical model.