Chapter 31. The Effect of Grain Size on the Toughness of Sintered Si3N4

  1. John B. Wachtman Jr.
  1. Keiji Matsuhiro and
  2. Tomonori Takahashi

Published Online: 26 MAR 2008

DOI: 10.1002/9780470310557.ch31

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

Matsuhiro, K. and Takahashi, T. (1989) The Effect of Grain Size on the Toughness of Sintered Si3N4, 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.ch31

Author Information

  1. Materials Research Lab. NGK Insulators, Ltd. Mizuho, Nagoya 467 Japan

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 diffractometry;
  • crack propagation;
  • chemical vapor infiltration;
  • monolithic ceramics;
  • chemical vapor deposition

Summary

Three distinctive sintered Si3N4, bodies were prepared and characterized on their toughness-controlling parameters. High strength sintered Si3N4 bodies having K1C value of 6.5, 8.3, and 9.7MNm−3/2, respectively, were obtained by different chemistry, starting powders, and sintering conditions. The coarser microstructure body showed the tougher property. Grain size analysis results showed that β-Si3N4 grain having a diameter larger than 1 μm affected primarily by increased toughness. Crack propagation analysis showed the more frequently deflected and branched crack propagation gave the higher toughness. These results concluded that crack deflection and branching occurred preferably at the site of the β-Si3N4 grain having larger than 1 μm diameter. Consequently K1C of the coarse grain sintered Si3O4 was relatively higher than that of the fine grain one.