Chapter 41. Time Evolution of Microstructure During Forced Flow Chemical Vapor Infiltration of a Continuous Fiber Ceramic Matrix Composite
- John B. Wachtman Jr.
Published Online: 26 MAR 2008
Copyright © 1993 The American Ceramic Society
Proceedings of the 17th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 14, Issue 9/10
How to Cite
Kinney, J. H., Haupt, D. L., Breunig, T. M., Nichols, M. C., Starr, T. L. and Stock, S. R. (1993) Time Evolution of Microstructure During Forced Flow Chemical Vapor Infiltration of a Continuous Fiber Ceramic Matrix Composite, in Proceedings of the 17th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 14, Issue 9/10 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314234.ch41
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 1993
Print ISBN: 9780470375273
Online ISBN: 9780470314234
- matrix material;
X-ray Tomographic Microscopy (XTM) is a high resolution technique for noninvasively imaging a material's microstructure in three dimensions. XTM has a spatial resolution which is sufficient to image micro-and macroporosity in continuous fiber ceramic matrix composites; hence, the technique is ideal for following, in situ, time evolution of matrix growth and consolidation during chemical vapor infiltration (CVI) processing. We report the results of the first XTM experiments where matrix growth has been measured in situ during CVI. Two square-weave Nicalon fiber preform architectures (0/45 and 0/90) were imaged during isothermal forced infiltration with MTS at 975°C. The filling of the micropores within the fiber tows was followed as a function of both position within the preform and infiltration time. Measurements of surface area and local density were also obtained as a function of the processing time. The observations support a surface area model which depends only upon fractional density and not upon fiber architecture or position within the preform.