16. Damage Detection of Thermal Barrier Coatings by Electrochemical Impedance Spectroscopy

  1. Dongming Zhu and
  2. Kevin Plucknett
  1. B. Jayaraj,
  2. S. Vishweswaraiah,
  3. V. H. Desai and
  4. Y. H. Sohn

Published Online: 26 MAR 2008

DOI: 10.1002/9780470291238.ch16

Advances in Ceramic Coatings and Ceramic-Metal Systems: Ceramic Engineering and Science Proceedings, Volume 26, Number 3

Advances in Ceramic Coatings and Ceramic-Metal Systems: Ceramic Engineering and Science Proceedings, Volume 26, Number 3

How to Cite

Jayaraj, B., Vishweswaraiah, S., Desai, V. H. and Sohn, Y. H. (2005) Damage Detection of Thermal Barrier Coatings by Electrochemical Impedance Spectroscopy, in Advances in Ceramic Coatings and Ceramic-Metal Systems: Ceramic Engineering and Science Proceedings, Volume 26, Number 3 (eds D. Zhu and K. Plucknett), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470291238.ch16

Author Information

  1. Advanced Materials Processing and Analysis Center and Department of Mechanical, Materials and Aerospace Engineering University of Central Florida Orlando, Florida, 32816-2455

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 2005

ISBN Information

Print ISBN: 9781574982336

Online ISBN: 9780470291238

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Keywords:

  • electrochemical;
  • monolithic;
  • isothermal;
  • thormography;
  • spectroscopy

Summary

Thermal barrier coatings (TBCs), consisting of yttria-stabilized zirconia (YSZ) on NiCoCrAlY or aluminide bond coats, protect hot-section components, such as blades and vanes of advanced gas turbine engines. Electrochemical impedance spectroscopy (EIS) is being developed as a non-destructive evaluation (NDE) technique for TBCs. For better understanding of electrochemical impedance response of TBCs and their damage after high temperature exposure (isothermal/cyclic), monolithic YSZ with open pores and alumina-forming NiAl specimens were independently examined by EIS as a function of isothermal oxidation. Impedance of the YSZ and oxidized NiAl increased with high temperature sintering and oxide-scale growth, respectively. However, the electrochemical impedance was significantly reduced when quench-cracks in sintered YSZ or spallation of oxide-scale from the NiAl were observed. These observations are correlated to the electrochemical impedance response of a TBC system consisting of electron beam physical vapor deposited (EB-PVD) YSZ and (Ni, Pt)Al bond coats as a function of isothermal oxidation.