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Silsesquioxane-derived ceramic fibresFibers formed from blends of silsesquioxane polymers were characterized to study the pyrolytic conversion of these precursors to ceramics. The morphology of fibers pyrolyzed to 1400 C revealed primarily amorphous glasses whose conversion to beta-SiC is a function of both blend composition and pyrolysis conditions. Formation of beta-SiC crystallites within the glassy phase is favored by higher than stoichiometric C/Si ratios, while carbothermal reduction of Si-O bonds to form SiC with loss of SiO and CO occurs at higher methyl/phenylpropyl silsesquioxane (lower C/Si) ratios. As the carbothermal reduction is assumed to be diffusion controlled, the fibers can serve as model systems to gain understanding of the silsesquioxane pyrolysis behavior, and therefore are useful in the development of polysilsesquioxane-derived ceramic matrices and coatings as well.
Document ID
19910045660
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Hurwitz, F. I. (NASA Lewis Research Center Cleveland, OH, United States)
Farmer, S. C. (NASA Lewis Research Center Cleveland, OH, United States)
Terepka, F. M. (NASA Lewis Research Center Cleveland, OH, United States)
Leonhardt, T. A. (Sverdrup Technology, Inc. Cleveland, OH, United States)
Date Acquired
August 14, 2013
Publication Date
March 1, 1991
Publication Information
Publication: Journal of Materials Science
Volume: 26
ISSN: 0022-2461
Subject Category
NONMETALLIC MATERIALS
Distribution Limits
Public
Copyright
Other