| About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
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| Symposium
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Advances in High-Temperature Oxidation and Degradation of Materials for Harsh Environments: A SMD and FMD Symposium Honoring Brian Gleeson
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| Presentation Title |
Thermochemical Stability of Yb2Si2O7-Yb2SiO5 Mixtures in High-Temperature Water Vapor Environments |
| Author(s) |
Chathuranga Sandamal Witharamage, Wesley Jackson, Elizabeth J Opila |
| On-Site Speaker (Planned) |
Chathuranga Sandamal Witharamage |
| Abstract Scope |
Rare earth disilicates are used as environmental barrier coatings (EBCs) for ceramic matrix composite components in turbine engine environments. However, these EBCs still react with water vapor to form volatile silicon hydroxide species and rare earth monosilicates. Therefore, further development is needed to enhance their degradation resistance in high-temperature water vapor environments. In this study, mixtures of Yb2Si2O7 (YbDS) and Yb2SiO5 (YbMS) were synthesized by dispersing 10 and 30 vol.% YbMS in a YbDS matrix. The thermochemical stability of the synthesized coupons was studied in high-velocity water vapor at temperatures between 1200-1400 °C. Scanning electron microscopy and x-ray diffraction analysis revealed silica depletion from the YbDS matrix, forming YbMS in all compositions. The thickness of the reaction product layer of each system was measured as a function of exposure time and temperature to determine the reaction kinetics. Preliminary results indicated that YbDS-10% YbMS is most resistant to water vapor attack. |