8. On the Thermal Cycling and Evolution of Surface Morphology for Thermally Cycled NiCoCrAlY Bondcoats

  1. Dongming Zhu and
  2. Kevin Plucknett
  1. Jun Shi1,
  2. Anette M. Karlsson1,
  3. Bernd Baufeld2 and
  4. Marion Bartsch2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470291238.ch8

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

Shi, J., Karlsson, A. M., Baufeld, B. and Bartsch, M. (2008) On the Thermal Cycling and Evolution of Surface Morphology for Thermally Cycled NiCoCrAlY Bondcoats, 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.ch8

Author Information

  1. 1

    University of Delaware 126 Spencer Laboratory Newark, DE, 19716-3140, USA

  2. 2

    The German Aerospace Center (DLR) D-51147 Cologne, Germany

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:

  • morphology;
  • parameters;
  • alumina;
  • phenomenon;
  • thermocouples

Summary

Morphological instabilities such as rumpling and ratcheting on bond coat surfaces in thermal barrier coatings (TBCs) have recently received significant attention since these phenomena can be directly linked to system failures. Recent observations from thermo-mechanically cycled TBC-samples reveal that, if the ceramic top coat has spalled, the morphological evolution of a NiCoCrAlY bond coat can be linked to the presence or absence of a thermal gradient over the coating. Morphological instabilities develop during cycling with a thermal gradient while the surface remains smooth for cyclic conditions without a gradient. This paper discusses an initial numerical model to simulate this behavior, lending itself to some insight in the thermo-mechanical response. In particular, it is shown that not only is the thermal gradient important, but the relative rate between the inside and outside heating/cooling sequence plays a significant role in driving the morphological instabilities.