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Role of interfacial carbon layer in the thermal diffusivity/conductivity of silicon carbide fiber-reinforced reaction-bonded silicon nitride matrix compositesExperiments were carried out on samples of reaction-bonded silicon nitride uniaxially reinforced by SiC monofilaments with and without a 3-micron-thick carbon-rich coating. It is found that a combination of a carbon coatings on the fibers and an interfacial gap due to the thermal expansion mismatch in the composite can significantly (by a factor of 2) lower the effective thermal diffusivity in the direction transverse to the fiber. At atmospheric pressure, gaseous conduction across the interfacial gap makes a significant contribution to the heat transfer across the interface, indicated by significantly lower values of the effective thermal diffusivity under vacuum than in nitrogen or helium at atmospheric pressure.
Document ID
19920042819
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Bhatt, Hemanshu
(NASA Lewis Research Center Cleveland, OH, United States)
Donaldson, Kimberly Y.
(NASA Lewis Research Center Cleveland, OH, United States)
Hasselman, D. P. H.
(Virginia Polytechnic Institute and State University Blacksburg, United States)
Bhatt, Ramakrishna T.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
August 15, 2013
Publication Date
February 1, 1992
Publication Information
Publication: American Ceramic Society, Journal
Volume: 75
ISSN: 0002-7820
Subject Category
Composite Materials
Accession Number
92A25443
Distribution Limits
Public
Copyright
Other

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