Abstract
A primary failure mode for environmental barrier coatings (EBCs) on SiC ceramic matrix composites (CMCs) is the oxidation of the intermediate Si-bond coating, where the formation of SiO2 at the bond coating–EBC interface results in debonding and spallation. This work compares the microstructure evolution and steam oxidation kinetics of the Si-bond coating beneath yttrium/ytterbium disilicate ((Y/Yb)DS) and ytterbium disilicate/monosilicate (YbDS/YbMS) EBCs to better understand the impact of EBC composition on oxidation kinetics. After 500 1-h cycles at 1350°C, (Y/Yb)DS displayed a decreasing concentration of the monosilicate minor phase and increasing concentration of porosity as furnace cycling time increased, whereas the YbDS/YbMS EBC displayed negligible microstructural evolution. For both EBC systems, thermally grown oxide growth rates in steam were found to increase by approximately an order magnitude compared to dry air oxidation. The (Y/Yb)DS EBC displayed a reduced steam oxidation rate compared to YbDS/YbMS.
| Original language | English |
|---|---|
| Pages (from-to) | 613-620 |
| Number of pages | 8 |
| Journal | Journal of the American Ceramic Society |
| Volume | 106 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 2023 |
Funding
The authors would like to thank V. Cox, T. Geer, C. O ’Dell, B. Johnston, G. Garner, and J. Wade, from ORNL, for their assistance with the experimental work. The authors would also like to thank D. Sulejmanovic and J. Jun for technical reviews at ORNL. This work was funded by the U.S. Department of Energy, Office of Fossil Energy and Carbon Management, Advanced Turbine Program (program manager R. Dennis and project monitor P. Burke at NETL). The authors would like to thank V. Cox, T. Geer, C. O ’Dell, B. Johnston, G. Garner, and J. Wade, from ORNL, for their assistance with the experimental work. The authors would also like to thank D. Sulejmanovic and J. Jun for technical reviews at ORNL. This work was funded by the U.S. Department of Energy, Office of Fossil Energy and Carbon Management, Advanced Turbine Program (program manager R. Dennis and project monitor P. Burke at NETL). This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan. http://energy.gov/downloads/doe-public-access-plan).
Keywords
- Raman spectroscopy
- environmental barrier coatings (EBC)
- oxidation