19. Effect of Monazite Coating on Tensile Behavior of Nextel™ 720 Fibers at High Temperatures

  1. Edgar Lara-Curzio and
  2. Michael J. Readey
  1. D. M. Pai1,
  2. S. Yarmolenko1,
  3. E. Freeman1,
  4. J. Sankar1 and
  5. L. P. Zawada2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470291191.ch19

28th International Conference on Advanced Ceramics and Composites B: Ceramic Engineering and Science Proceedings, Volume 25, Issue 4

28th International Conference on Advanced Ceramics and Composites B: Ceramic Engineering and Science Proceedings, Volume 25, Issue 4

How to Cite

Pai, D. M., Yarmolenko, S., Freeman, E., Sankar, J. and Zawada, L. P. (2004) Effect of Monazite Coating on Tensile Behavior of Nextel™ 720 Fibers at High Temperatures, in 28th International Conference on Advanced Ceramics and Composites B: Ceramic Engineering and Science Proceedings, Volume 25, Issue 4 (eds E. Lara-Curzio and M. J. Readey), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470291191.ch19

Author Information

  1. 1

    Center for Advanced Materials and Smart Structures Department of Mechanical and Chemical Engineering North Carolina A&T State University Greensboro, NC 27411

  2. 2

    U. S. Air Force Research Laboratory Wright-Patterson AFB, OH 45433

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 2004

ISBN Information

Print ISBN: 9780470051528

Online ISBN: 9780470291191

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Keywords:

  • ceramic matrix composites;
  • room temperature;
  • weibull moduli;
  • unsoaked fibers;
  • monazite coated fibers

Summary

The tensile strengths of Nextel™ 720 fibers were measured at room temperature (RT) and 1200°C (HT) to study the effects of monazite (LaPO4) coating. Tests were conducted on asreceived (unsoaked) materials as well as materials that had been thermally soaked at HT for 100 hours. There is close agreement between the Weibull modulus obtained from the statistical distribution of fracture strength and the Weibull modulus obtained from a study of the gage length dependence of strength. The monazite coating does not change the RT strength of unsoaked single fibers, but improves the HT strength retention capability of unsoaked fibers. The average strength retained by uncoated and coated fibers at HT is 54% and 74% of the RT value. This beneficial effect of the coating disappears after soaking - coated and uncoated fibers have an HT tensile strength of about 48% of RT value.