Chapter 4. Role of Interfacial Thermal Barrier in the Transverse Thermal Conductivity of Uniaxial SiC Fiber-Reinforced Reaction Bonded Silicon Nitride

  1. John B. Wachtman Jr.
  1. H. Bhatt1,
  2. K. Y. Donaldson1,
  3. D. P. H. Hasselman1 and
  4. R. T. Bhatt2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470313954.ch4

Proceedings of the 16th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 13, Issue 7/8

Proceedings of the 16th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 13, Issue 7/8

How to Cite

Bhatt, H., Donaldson, K. Y., Hasselman, D. P. H. and Bhatt, R. T. (1994) Role of Interfacial Thermal Barrier in the Transverse Thermal Conductivity of Uniaxial SiC Fiber-Reinforced Reaction Bonded Silicon Nitride, in Proceedings of the 16th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 13, Issue 7/8 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470313954.ch4

Author Information

  1. 1

    Department of Materials Engineering Virginia Polytechnic Institute and State University Blacksburg, Virginia 24061, USA

  2. 2

    Ceramics Branch, NASA Research Center Cleveland, Ohio 44135, USA

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 1994

ISBN Information

Print ISBN: 9780470375174

Online ISBN: 9780470313954

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Keywords:

  • thermal;
  • composite;
  • diameter;
  • stoichiometric;
  • nitrogen

Summary

An interfacial thermal barrier at the fiber-matrix interface in SiC fiber-reinforced RBSN was found to significantly affect the transverse thermal conductivity. Comparisons of data for composites with and without a fiber carbon coating showed that the presence of the coating reduces the effective thermal conductivity by about a factor of two, partially due to an interfacial gap in the composites with coated fibers caused by the thermal expansion mismatch between the fibers and matrix. Gaseous heat transfer across this interfacial gap causes the thermal conductivity to depend on the gaseous environment. Oxidation of the coating results in a further reduction in thermal conductivity and a greater contribution of the interfacial gaseous heat transfer. Hot-isostatic-pressing of composites with the coated fibers resulted in a major increase in the thermal conductivity due to improved thermal contact across the fiber-matrix interface, increased density of the matrix phase and enhanced thermal conductivity of the fibers due to an increase in the grain sue and crystallinity.