60. Effects of Bond Coat Surface Roughness and Pre-Oxidation on the Thermal Cycling Lifetime of Thermal Barrier Coatings

  1. Edgar Lara-Curzio and
  2. Michael J. Readey
  1. J. Liu and
  2. Y. H. Sohn

Published Online: 26 MAR 2008

DOI: 10.1002/9780470291191.ch60

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

Liu, J. and Sohn, Y. H. (2004) Effects of Bond Coat Surface Roughness and Pre-Oxidation on the Thermal Cycling Lifetime of Thermal Barrier Coatings, 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.ch60

Author Information

  1. Advanced Materials Processing and Analysis Center University of Central Florida Orlando, FL 32816

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:

  • compressive creep tests;
  • thermal barrier coatings;
  • zirconia;
  • ceramics;
  • scanning electron microscopy

Summary

Effects of surface roughness and pre-oxidation heat treatment for the NiCoCrAlY bond coat (PWA276), carried out prior to the electron beam physical vapor deposition (EB-PVD) of ZrO2-7 wt% Y2O3 (7YSZ) ceramic topcoat, on the thermal cycling lifetime of thermal barrier coatings (TBCs) were examined. As a function of bond coat processing and thermal cycling, TBCs were characterized by using optical profilometry, photo-stimulated luminescence spectroscopy (PSLS), optical microscopy, and scanning electron microscopy. TBC specimens with preoxidized bond coats, in general, exhibited longer lifetime than those without pre-oxidation. The longest TBC lifetime was observed when hand-polished (i. e., smoothest) bond coats were preoxidized prior to EB-PVD of 7YSZ. However, without pre-oxidation, TBC specimen with handpolished and barrel-finished bond coats failed prematurely due to underdeveloped thermally grown oxide (TGO) and/or failure at the YSZ/TGO interfaces. For TBCs specimens with preoxidized bond coats, a greater lifetime was observed with a higher initial compressive residual stress within the TGO.