19. Crack Driving Forces in a Multilayered Coating System for Ceramic Matrix Composite Substrates

  1. Dongming Zhu and
  2. Kevin Plucknett
  1. Louis J. Ghosn1,
  2. Dong Ming Zhu2 and
  3. Robert A. Miller3

Published Online: 26 MAR 2008

DOI: 10.1002/9780470291238.ch19

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

Ghosn, L. J., Zhu, D. M. and Miller, R. A. (2005) Crack Driving Forces in a Multilayered Coating System for Ceramic Matrix Composite Substrates, 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.ch19

Author Information

  1. 1

    Ohio Aerospace Institute NASA Glenn Research Center Cleveland, OH, 44135

  2. 2

    U.S. Army Research Laboratory NASA Glenn Research Center Cleveland, OH, 44135

  3. 3

    National Aeronautics and Space Administration Glenn Research Center Cleveland, OH, 44135

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:

  • thermal;
  • environment;
  • composites;
  • pryochlore;
  • ceramic

Summary

The effects of the top coating thickness, modulus and shrinkage strains on the crack driving forces for a baseline multi-layer Yttria-Stabilized-Zirconia/Mullite/Si thermal and environment barrier coating (TEBC) system for SiC/SiC ceramic matrix composite substrates are determined for gas turbine applications. The crack driving forces increase with increasing modulus, and a low modulus thermal barrier coating material (below 10GPa) will have no cracking issues under the thermal gradient condition analyzed. Since top coating sintering increases the crack driving forces with time, highly sintering resistant coatings are desirable to maintain a low tensile modulus and maintain a low crack driving force with time. Finite element results demonstrated that an advanced TEBC system, such as ZrO2/HfO2, which possesses improved sintering resistance and high temperature stability, exhibited excellent durability. A multi-vertical cracked structure with fine columnar spacing is an ideal strain tolerant coating capable of reducing the crack driving forces to an acceptable level even with a high modulus of 50GPa.