| Home | Log-in | Admin | Sitemap |
Home | Program | Detailed Program
Detailed Program
Paper Number : AD-I05
Time Frame : 16:55~17:20
Presentation Date : Thurseday, 27, November
Session Name : Advanced Coating for Gas Turbines
Session Chair 1# : Keesung Lee
Session Chair 2# : Byung-Koog Jang
Development of Oxides Eutectic EBC for Silicon Nitride Ceramics
Shunkichi UENO
Nihon University
In this paper, the corrosion and recession behavior of Lu2Si2O7/Al6Si2O13 (mullite) eutectic oxide phase that discovered by the authors in the Lu2O3-SiO2-Al2O3 ternary system were discussed. The eutectic point was approximately at 1510¡ÆC. It was found that the thermal expansion coefficient of eutectic oxide is comparable to those Si-based ceramic materials. Thus, it was surmised that this eutectic oxide could be potential candidate for environmental barrier coating (EBC) system for these Si-based ceramics because of its high eutectic point. The corrosion and recession tests were performed for eutectic bulks at 1300¡ÆC under the static water vapor environment and high speed stem jet environment. Results showed that there was little or no corrosion observed after the static state corrosion test. Since no boundary phase exists in this eutectic oxide, no selective corrosion of the boundary phase occurred during the test. The eutectic oxide film was then prepared on silicon nitride surface via the reaction sintering method. The water vapor corrosion test for silicon nitride with the eutectic oxide film was performed at 1300oC for up to 500h. However, mullite phase decomposed and removed after recession test under high speed steam jet test. A silicon nitride with multi-layered environmental barrier coating (EBC) system was prepared and the recession test for this sample was performed at 1300oC for 500 hours using high-speed steam jet equipment, which was employed to simulate the gas turbine engine conditions. Post-test examinations showed that the multi-layered EBC system well sustained during the high-temperature steam jet test. Also, the silicon nitride substrate was protected from the oxidation and corrosion, and thus no material recession was observed.


Acknowledgements :