Chapter 42. Quasistatic vs. Dynamic Modulus Measurements of Plasma–Sprayed Thermal Barrier Coatings

  1. Hau-Tay Lin and
  2. Mrityunjay Singh
  1. J. I. Eldridge,
  2. G. N. Morscher and
  3. S. R. Choi

Published Online: 26 MAR 2008

DOI: 10.1002/9780470294758.ch42

26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 23, Issue 4

26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 23, Issue 4

How to Cite

Eldridge, J. I., Morscher, G. N. and Choi, S. R. (2002) Quasistatic vs. Dynamic Modulus Measurements of Plasma–Sprayed Thermal Barrier Coatings, in 26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 23, Issue 4 (eds H.-T. Lin and M. Singh), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294758.ch42

Author Information

  1. NASA Glenn Research Center Cleveland, OH 44135

Publication History

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

ISBN Information

Print ISBN: 9780470375792

Online ISBN: 9780470294758

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Keywords:

  • plasma-sprayed thermal;
  • stabilized zirconia;
  • quasistatic cyclic compression;
  • sound velocity;
  • elastic behavior

Summary

Plasma-sprayed 8wt% yttria-stabilized zirconia (8YSZ) thermal barrier coatings (TBCs) have been demonstrated to exhibit nonlinear hysteretic elastic behavior by quasistatic cyclic compression and cylindrical punch indentation measurements. In particular, the instantaneous (tangential) elastic modulus increases with applied stress and exhibits significant hysteresis during cycling. Sound velocity (dynamic) measurements also show an increase in TBC modulus with applied compressive stress, but in contrast, show no significant hysteresis for the modulus during cycling. The nonlinear elastic behavior of the TBCs evidenced by these tests is attributed to coating compaction and internal sliding. The differences between the quasistatic and dynamic measurements are explained by the relative absence of the effect of internal sliding in the dynamic modulus measurements. By incorporating short load reversals into the larger loading cycle and measuring the instantaneous modulus at the start of each load reversal, the effects of internal sliding can be substantially reduced in the quasistatic measurements, and the resulting modulus values show good agreement with the modulus values determined by dynamic sound velocity measurements.