Chapter 8. Effect of Porosity on Hertzian Contact Damage in Silicon-Nitride Ceramics

  1. Hua-Tay Lin and
  2. Mrityunjay Singh
  1. J.H. She1,
  2. J.F. Yang2,
  3. Y. Beppu3 and
  4. T. Ohji4

Published Online: 26 MAR 2008

DOI: 10.1002/9780470294741.ch8

26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 23, Issue 3

26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 23, Issue 3

How to Cite

She, J.H., Yang, J.F., Beppu, Y. and Ohji, T. (2002) Effect of Porosity on Hertzian Contact Damage in Silicon-Nitride Ceramics, in 26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 23, Issue 3 (eds H.-T. Lin and M. Singh), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294741.ch8

Author Information

  1. 1

    Synergy Materials Research Center, AIST Nagoya 463–8687, Japan

  2. 2

    Japan Science and Technology Corporation Nagoya 463–8687, Japan

  3. 3

    Synergy Ceramics Laboratory, FCRA Nagoya 463–8687, Japan

  4. 4

    Synergy Materials Research Center, AIST Nagoya 463–8687, Japan

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 2002

ISBN Information

Print ISBN: 9780470375785

Online ISBN: 9780470294741

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Keywords:

  • intragrandar;
  • microfracture;
  • degradation;
  • ceramics;
  • indentations

Summary

Hertzian indentation tests were performed to investigate the effect of porosity on the contact damage behavior of Si3N4 ceramics. Using a bonded-interface technique, the Hertzian contact damage patterns were examined. As a result of intragranular microfracture under Hertzian contact, a distributed subsurface damage region is developed in highly porous Si3N4 ceramics. In contrast, low-porosity Si3N4, shows a classical cone crack. Regardless of these two distinct damage modes, all the damaged specimens were observed to fail from the contact center in three-point bending tests. However, low-porosity Si3N4 exhibits an abrupt strength loss when the indentation load exceeds a critical value, while highly porous Si3N4 shows a gradual strength degradation.