Phase composition and microstructural responses of crystalline mullite/YSZ coating under water vapor environments
| Autor: | García Granados, Eugenio Santiago, Mesquita-Guimarães, J., Miranzo López, Pilar, Osendi, María Isabel, Cojocaru, C. V., Wang, Y., Moreau, C., Lima, R. S. |
|---|---|
| Rok vydání: | 2010 |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| Popis: | 4 páginas, 6 figuras.-- Comunicación presentada al 33th International Thermal Spray Conference & Exposition 2010; Thermal Spray: Global Solutions for Future Applications.-- Publicado como artículo en Physical Chemistry Chemical Physics 20(1-2): 83-91 (2011). Mullite and mullite/ZrO2 bi-layer systems are being considered as environment barrier coatings (EBCs) for protection of Si-based (Si3N4, SiC) substrates against water vapor corrosion for application in forthcoming turbine engines. An approach to reduce the thermal expansion mismatch between mullite and ZrO2 layers in those coatings would be to tailor intermediate mullite/Y-ZrO2 composite layers. The feasibility of these composite layers is studied in a comparative manner by plasma spraying both single mullite and bi-layer coatings of mullite and of mullite/ Y-ZrO2 (75/25 vol %.) over Hexoloy SiC substrates. All feedstock materials are equally prepared using spray drying methods as the mix powders are not commercially available. Singular spraying conditions are used to assure enhanced crystallization of the mullite phase. Coatings are aged for 100 h at 1300 ºC in a controlled water vapor environment. The effect of water corrosion on the exposed coatings is comparatively investigated, determining changes in crystalline phase by X- ray diffraction (XRD), the crystallization of amorphous phases is highlighted by the use of differential thermal analysis (DTA) tools and the microstructure of the polished coatings is analyzed by scanning electron microscopy (SEM). This work has been supported by NRC-CSIC program (project 2007CA003) and MICINN (Ministry of Science and Innovation, Spain) under project MAT2006- 07118. One of the authors (Eugenio Garcia) acknowledges the Ramón y Cajal Program (MICINN) for his financial support. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|