Chapter 9. Strength of Reaction Bonded Silicon Nitride After High Temperature Air Exposures

  1. John B. Wachtman Jr.
  1. J. E. Ritter1,
  2. P. A. Gennari1,
  3. S. V. Nair1,
  4. J. S. Haggerty2 and
  5. A. Lightfoot2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470310557.ch9

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

Ritter, J. E., Gennari, P. A., Nair, S. V., Haggerty, J. S. and Lightfoot, A. (1989) Strength of Reaction Bonded Silicon Nitride After High Temperature Air Exposures, 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.ch9

Author Information

  1. 1

    University of Massachusetts Amherst, MA 01003

  2. 2

    Massachusetts Institute of Technology Cambridge, MA 02139

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:

  • chemical vapor infiltration;
  • oxidation products;
  • x-ray analysis;
  • fractography;
  • cristobalite

Summary

The effects of high-temperature exposures on the room-temperature strength of RBSN made from high purity Si powder have been studied. Oxidation at 1000°C in air for 1 h revealed no evidence of an oxide layer by SEM, and only a ≈0.6 μm layer after 50 h. After oxidation at 1400°C, SEM indicated a ≈0.5 μm layer formed in 1 h and a ≈1.5 μm layer formed in 50 h. The 1400°-50 h layers exhibited a uniform 3–5 μm crack pattern; however, these cracks did not penetrate into the RBSN substrates. Contrary to conventional RBSN, these oxidizing exposures did not change the strength or the fracture toughness of the high purity RBSN (MOR = 435 ± 120 MPa and KIC = 2.1 ± 0.5 MPa · m1/2). This superior oxidation resistance resulted from the purity and the small channel diameters achieved in the SiH4 derived RBSN.