67. Functionally Graded CVD Mullite Environmental Barrier Coatings

  1. Edgar Lara-Curzio and
  2. Michael J. Readey
  1. S. N. Basu and
  2. V. K. Sarin

Published Online: 26 MAR 2008

DOI: 10.1002/9780470291191.ch67

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

Basu, S. N. and Sarin, V. K. (2004) Functionally Graded CVD Mullite Environmental 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.ch67

Author Information

  1. Department of Manufacturing Engineering Boston University Brooklne, MA 02446

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:

  • liquid natural gas;
  • ceramic matrix composites;
  • environmental barrier coatings;
  • energy dispersive qectmmpy;
  • x-ray diffraction

Summary

Functionally graded mullite coatings have been deposited on flat SiC substrates and on SiC fibers by chemical vapor deposition. The composition of the coating was varied from nearstoichiometric mullite (3Al2O3·2SiO2) at the coating/substrate interface to approximately t-Al2O3, a derivative of the mullite structure in which all Si had been replaced by Al, at the coating surface. These mullite coatings were adherent on thermal cycling and exhibited excellent high temperature oxidation and hot corrosion resistance. Mullite has a close CTE match with SiC, accounting for superior coating adhesion, while the coating surface in contact with aggressive environments was virtually Si-free, accounting for improved hot-corrosion resistance.