Chapter 15. Properties of Ceramics in the NbB2–CrB2 System

  1. John B. Wachtman Jr.
  1. I. G. Talmy,
  2. E. J. Wuchina,
  3. J. A. Zaykoslr and
  4. M. M. Opeka

Published Online: 26 MAR 2008

DOI: 10.1002/9780470314821.ch15

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

Talmy, I. G., Wuchina, E. J., Zaykoslr, J. A. and Opeka, M. M. (2008) Properties of Ceramics in the NbB2–CrB2 System, 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.ch15

Author Information

  1. Naval Surface Warfare Center, 10901 New Hampshire Avenue, Silver Spring, MD 20903–5640

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:

  • formation;
  • solutions;
  • disparity;
  • oxidation;
  • thermal expansion

Summary

Phase equilibrium and properties of ceramics in the NbB2–CrB2 system were studied. Continuous solid solutions were found showing high activation energy (96 kcal/mol) of formation which is due to large disparity of atomic radii between Cr and Nb. Ceramics prepared by hot pressing at 1900–2100°C (depending on composition) were characterized by hardness, flexural strength, and oxidation resistance. The dependence of these properties on composition did not follow the rule of mixtures. The 40%NbB2/60%CrB2 composition was found to have high oxidation resistance and hardness. The effects of various modifying additives (such as Al2O3, SiB4, and SiC) on the mechanical properties and oxidation behavior of NbB2 and CrB2 ceramics are discussed