Phase equilibria in ZrO2-YO1.5-SiO2 (ZYS) and ZrO2-GdO1.5-SiO2 (ZGS) were experimentally assessed at 1400 °C and 1600 °C as they can offer insight on reactions between thermal barrier coatings (TBCs) based on ZrO2-YO1.5/GdO1.5 and molten silicate deposits in gas turbine engines. Features shared in both systems include the absence of ternary compounds and no ternary solubility in the binary phases. In ZYS however, a quaternary invariant reaction was observed that eliminates the zircon-disilicate equilibrium at higher temperatures. The results suggest no appreciable difference in the reactions between silica and thermal barrier oxides based on ZrO2-YO1.5 or ZrO2-GdO1.5, or environmental barrier coatings based on the corresponding Y/Gd silicates. The phase diagrams derived from these experiments are part of a broader effort to develop thermodynamic databases that can help guide the design of next-generation TBCs.
|Original language||English (US)|
|Number of pages||11|
|Journal||Journal of the European Ceramic Society|
|State||Published - Aug 2018|
Bibliographical noteFunding Information:
This investigation was supported by ONR under STTR N00014-17-C-2034 with Questek Innovations, monitored by Dr. David Shifler. CG thanks the NSF-sponsored CISEI program at UCSB for support toward his internship. The work made use of the MRL Shared Experimental Facilities supported by the MRSEC Program of the NSF under Award No. DMR 1720256; a member of the NSF-funded Materials Research Facilities Network ( www.mrfn.org ). The authors are grateful to Dr. G.G.E. Seward (UCSB) for assistance with EPMA measurements and Ms. T.L. Barth, Ms. A.J. Velasco-Hogan and Mr. S. Molakalapalli (UCSB) for assistance with sample preparation.
© 2018 Elsevier Ltd
- Phase diagrams
- Phase equilibria
- Rare earth zirconates
- Thermal barrier coatings