Steam oxidation and microstructural evolution of rare earth silicate environmental barrier coatings
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Stony Brook Univ., NY (United States)
- Praxair, Inc., Danbury, CT (United States)
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.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Fossil Energy (FE); USDOE Office of Fossil Energy and Carbon Management (FECM)
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1994735
- Journal Information:
- Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 1 Vol. 106; ISSN 0002-7820
- Publisher:
- American Ceramic SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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