Internal stresses and phase stability in multiphase environmental barrier coatings
Abstract
The use of silicon-based ceramics in power generation applications is limited by recession of the passivating SiO2 when it reacts with water-vapor to form a volatile hydroxide. Environmental barrier coatings are used to prevent diffusion of reactive species to the structural ceramic substrate. Often these barriers are multilayered and/or multiphase to provide optimal thermal expansion match, microstructural stability, as well as low diffusivities. High energy X-rays are used to assess internal stress as well as phase content and stability in two coating systems: alloyed Ta_2O_5 for Si_3N_4 and strontium-aluminosilicates for SiC/SiC. In particular, the role of phase transitions and precipitation on the coating internal stresses is evaluated along with their ramifications for coating lifetime.
Additional Information
© 2007 Carl Hanser Verlag GmbH & Co. KG. Received June 25, 2007; accepted September 4, 2007. This work was supported, in part, by the U.S. Department of Energy through Argonne National Laboratory and the University of Chicago under Award No. DE-AC02-06CH11357. Use of the Advanced Photon Source was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Science, under contract number W-31-109-Eng-38. The authors would like to acknowledge Jim Guiheen from Honeywell International for his assistance in the Ta_2O_5- based work including procuring alloyed powders and thermal cycling of samples.Additional details
- Eprint ID
- 47169
- DOI
- 10.3139/146.101590
- Resolver ID
- CaltechAUTHORS:20140714-103602932
- DE-AC02-06CH11357
- Department of Energy (DOE)
- W-31-109-Eng-38
- Department of Energy (DOE)
- Created
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2014-07-14Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field