We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Thermochemical Interaction of Thermal Barrier Coatings with Molten CaO–MgO–Al<sub>2</sub>O<sub>3</sub>–SiO<sub>2</sub> (CMAS) Deposits.
- Authors
Krämer, Stephan; Yang, James; Levi, Carlos G.; Johnson, Curtis A.
- Abstract
Thermal barrier coatings (TBCs) are increasingly susceptible to degradation by molten calcium–magnesium alumino silicate (CMAS) deposits in advanced engines that operate at higher temperatures and in environments laden with siliceous debris. This paper investigates the thermochemical aspects of the degradation phenomena using a model CMAS composition and ZrO2–7.6%YO1.5 (7YSZ) grown by vapor deposition on alumina substrates. The changes in microstructure and chemistry are characterized after isothermal treatments of 4 h at 1200°–1400°C. It is found that CMAS rapidly penetrates the open structure of the coating as soon as melting occurs, whereupon the original 7YSZ dissolves in the CMAS and reprecipitates with a different morphology and composition that depends on the local melt chemistry. The attack is minimal in the bulk of the coating but severe near the surface and the interface with the substrate, which is also partially dissolved by the melt. The phase evolution is discussed in terms of available thermodynamic information.
- Subjects
AERODYNAMIC heating; VAPOR-plating; SURFACE coatings; ALUMINUM oxide; MAGNESIUM; SILICATES
- Publication
Journal of the American Ceramic Society, 2006, Vol 89, Issue 10, p3167
- ISSN
0002-7820
- Publication type
Article
- DOI
10.1111/j.1551-2916.2006.01209.x