Chapter 42. Comparison of Properties for Formulations Prepared from Two Silicon Nitride Powders

  1. John B. Wachtman Jr.
  1. D. E. Wittmer1,
  2. B. E. Rodely1,
  3. V. A. Knapp1,
  4. S. P. Etherton1 and
  5. C. W. Miller Jr.2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470314821.ch42

Proceedings of the 20th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A: Ceramic Engineering and Science Proceedings, Volume 17, Issue 3

Proceedings of the 20th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A: Ceramic Engineering and Science Proceedings, Volume 17, Issue 3

How to Cite

Wittmer, D. E., Rodely, B. E., Knapp, V. A., Etherton, S. P. and Miller, C. W. (1996) Comparison of Properties for Formulations Prepared from Two Silicon Nitride Powders, in Proceedings of the 20th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A: Ceramic Engineering and Science Proceedings, Volume 17, Issue 3 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314821.ch42

Author Information

  1. 1

    Southern Illinois University, Carbondale, IL

  2. 2

    Centorr/Vacuum Industries, Inc., Nashua, NH

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 1996

ISBN Information

Print ISBN: 9780470375426

Online ISBN: 9780470314821

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Keywords:

  • turbomilling;
  • formulations;
  • theoretical densities;
  • flexural;
  • characteristics

Summary

A comparative analysis was made of two Si3N4 powders, a new pilot scale low-cost Si3N4 manufactured by Dow Chemical Company (DCC-SN) and a commercially available, high-purity Si3N4 (E-10) produced by Ube Industries. Three formulations, containing Al2O3 and Y2O3 sintering aids (A2Y6, A2Y8, and A4Y6), were processed using the two Si3N3 powders. After turbomilling, pressure casting, drying, and isopressing, the formed disks were continuously sintered at 1775OC for 90 min. The sintered disks were machined into type B test bars for measurement of density, room-temperature and elevated temperature four-point flexural strength, and fracture toughness. Polished test bars were microwave plasma etched prior to microstructural analysis by SEM. Elevated temperature four-point flexural strength was determined at 850, 1000, 1200 and 1350°C. In general, the properties obtained for all formulations processed with Ube E-10 were more acceptable than those for DCC-SN, since the DCC-SN compositions did not sinter to Full density.