Chapter 55. Degradation of SiC Whiskers at Elevated Temperatures

  1. John B. Wachtman Jr.
  1. A. J. Whitehead1,
  2. T. F. Page1 and
  3. I. Hlggins2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470310557.ch55

A Collection of Papers Presented at the 13th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 10, Issue 7/8

A Collection of Papers Presented at the 13th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 10, Issue 7/8

How to Cite

Whitehead, A. J., Page, T. F. and Hlggins, I. (2008) Degradation of SiC Whiskers at Elevated Temperatures, in A Collection of Papers Presented at the 13th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 10, Issue 7/8 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470310557.ch55

Author Information

  1. 1

    University of Newcastle-upon-Tyne Newcastle-upon-Tyne, UK

  2. 2

    UKAEA, Springfields Preston, UK

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 1989

ISBN Information

Print ISBN: 9780470374863

Online ISBN: 9780470310557

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Keywords:

  • x-ray powder diffraction;
  • whiskers;
  • chemical vapor infiltration;
  • silicon carbide;
  • scanning electron microscopy

Summary

Detrimental changes to the morphology, microstructure, and chemistry of silicon carbide whisker materials can occur during the fabrication of ceramic matrix composites. To explore the possible effects of heat treatment on both whisker morphology and pofytype, β-SiC whiskers have been examined after exposure to elevated temperatures (1850°–2150°C) for varying times in controlled atmospheres. Morphological changes have been followed by SEM and transformation in poly type by using XRD and TEM. It has been found that changes in shape occur extremely rapidly above 200VC, but that pofytype transformations (from β to a) appear to be much slower. Suggestions are made as to the mechanism by which the morphological changes occur and how these are related to the changes in pofytype. The implications for composite fabrication are discussed in terms of a thermal stability envelope inside which little change in whisker morphology is expected to occur during processing.