Chapter 25. Determination of Strength of Double-Layer Brittle Coatings on Metallic Substrates by Four-Point Bend Test

  1. Todd Jessen and
  2. Ersan Ustundag
  1. Ö. Ünal and
  2. D. J. Sordelet

Published Online: 28 MAR 2008

DOI: 10.1002/9780470294635.ch25

24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 21, Issue 4

24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 21, Issue 4

How to Cite

Ünal, Ö. and Sordelet, D. J. (2008) Determination of Strength of Double-Layer Brittle Coatings on Metallic Substrates by Four-Point Bend Test, in 24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 21, Issue 4 (eds T. Jessen and E. Ustundag), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294635.ch25

Author Information

  1. Ames Laboratory-USDOE, Ames, IA 50010

Publication History

  1. Published Online: 28 MAR 2008
  2. Published Print: 1 JAN 2000

ISBN Information

Print ISBN: 9780470375693

Online ISBN: 9780470294635

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Keywords:

  • brittle coatings;
  • residual stresses;
  • metallic substrates;
  • spallation;
  • double layer coatings

Summary

Apparent strength of ZrO2/Al2O3 double layer coatings on Al-alloy substrate was measured by four-point bend test. First, an analytical relationship between the strength and failure load was derived through the strength of materials approach. Second, failure load for the brittle coatings was determined experimentally. Finally, strength was calculated based on where the failure occurred. Since failure load strongly depends on residual stresses, the apparent strength determined reflects the effect of residual stresses. Calculations require the geometric dimensions as well as the elastic modulus of all three constituents.