X-ray tomographic study of chemical vapor infiltration processing of ceramic composites
- Lawrence Livermore National Lab., CA (United States)
- Sandia National Laboratories, Livermore, CA (United States)
- Georgia Inst. of Technology, Atlanta (United States)
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. 12 refs., 4 figs.
- DOE Contract Number:
- W-7405-ENG-48; AC04-76DP00789
- OSTI ID:
- 7369087
- Journal Information:
- Science (Washington, D.C.); (United States), Vol. 260:5109; ISSN 0036-8075
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CERAMICS
PRODUCTION
TOMOGRAPHY
COMPOSITE MATERIALS
SURFACE AREA
MATHEMATICAL MODELS
CHEMICAL VAPOR DEPOSITION
CRYSTAL GROWTH
MICROSCOPY
MICROSTRUCTURE
POROSITY
SILICON CARBIDES
X RADIATION
CARBIDES
CARBON COMPOUNDS
CHEMICAL COATING
DEPOSITION
DIAGNOSTIC TECHNIQUES
ELECTROMAGNETIC RADIATION
IONIZING RADIATIONS
MATERIALS
RADIATIONS
SILICON COMPOUNDS
SURFACE COATING
SURFACE PROPERTIES
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360201 - Ceramics
Cermets
& Refractories- Preparation & Fabrication