Abstract
Mixed Y and Yb disilicate coatings (Y/Yb)DS have been proposed as dual function thermal and environmental barrier coatings (EBCs) for protecting SiC-based ceramic matrix composites in gas-turbine environments. As an initial step, the 1350 °C dry air cyclic oxidation of atmospheric plasma sprayed (Y1.2/Yb0.8)DS and ytterbium disilicate/ytterbium monosilicate (YbDS/YbMS) EBCs deposited onto Si bond coatings was compared. As a baseline for evaluating EBC oxidant permeability, the dry air cyclic oxidation scale growth rates for bare silica formers (SiC, Si) were also measured and were consistently higher than rates previously measured after isothermal oxidation. Regarding Si bond coat oxidation rates underlying (Y/Yb)DS and YbDS/YbMS EBCs, the thinner silica scale formed under the thinner and denser (Y/Yb)DS coatings suggested a lower oxidant permeability than YbDS/YbMS. After 500 1-h cycles, the (Y/Yb)DS coating was comprised of only the β-polymorph disilicate and minor amounts of the X-2 phase monosilicate phase. Negligible differences in oxidation kinetics for (Y/Yb)DS coatings over the 90 – 240 µm thickness range were observed.
| Original language | English |
|---|---|
| Pages (from-to) | 3345-3350 |
| Number of pages | 6 |
| Journal | Journal of the European Ceramic Society |
| Volume | 42 |
| Issue number | 7 |
| DOIs | |
| State | Published - Jul 2022 |
Funding
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 ). The authors would like to thank E. Garcia and S. Sampath from the Center for Thermal Spray Research, Stony Brook University, and to V. Cox, T. Geer, C. O'Dell, B. Johnston, G. Garner, J. Wade, from ORNL. The authors would also like to thank Y. Su and D. Sulejmanovic for technical review at ORNL, and B. Harder from NASA for helpful comments on data analysis. Access to the Raman spectrometer was provided by the Nuclear Nonproliferation Division at ORNL. This work was funded by the Advanced Turbine Program (managed by R. Dennis at NETL), Office of Fossil Energy, Department of Energy. The authors would like to thank E. Garcia and S. Sampath from the Center for Thermal Spray Research, Stony Brook University, and to V. Cox, T. Geer, C. O’Dell, B. Johnston, G. Garner, J. Wade, from ORNL. The authors would also like to thank Y. Su and D. Sulejmanovic for technical review at ORNL, and B. Harder from NASA for helpful comments on data analysis. Access to the Raman spectrometer was provided by the Nuclear Nonproliferation Division at ORNL. This work was funded by the Advanced Turbine Program (managed by R. Dennis at NETL), Office of Fossil Energy, Department of Energy .
| Funders | Funder number |
|---|---|
| U.S. Department of Energy | |
| National Aeronautics and Space Administration | |
| Office of Fossil Energy | |
| Oak Ridge National Laboratory |
Keywords
- Environmental barrier coatings
- High temperature oxidation
- Rare-earth silicates
- Thermal barrier coatings