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3034 |
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Wednesday, September 28, 2011, Saal B2.2 11:00 AM New Processes 1 |
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Phase stability and performance of advanced composite environmental barrier coatings for SiC/SiC ceramic matrix composites |
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Dongming Zhu* / NASA Glenn Research Center, USA Bryan Harder/ NASA Glenn Research Center, USA Dennis S. Fox/ NASA Glenn Research Center, USA |
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Environmental barrier coatings (EBCs) will play a crucial role in advanced turbine engine systems because they can enable the use of light-weight hot-section SiC/SiC ceramic matrix composite (CMC) engine components, thereby significantly increasing engine operating temperatures and efficiency. Advanced environmental barrier coatings along with SiC/SiC CMC turbine airfoil and combustor technologies are being developed. With ever-increasing temperature and durability requirements for the environmental barrier coating systems, the development effort has been focused on advanced material systems and architectures to meet the engine component requirements. In this paper, the fundamental aspects of t ZrO2 and ytterbium silicate composite environmental barrier coating systems, processed using high temperature Plasma Spray - Physical Vapor Deposition (PS-PVD) and Atmospheric Plasma-Spray (APS), are studied in the EBC-SiC/SiC CMC configurations. The emphasis is placed on understanding the phase and environmental stability, thermal conductivity, interface reactions, and cyclic resistance of the PS-PVD and APS composite coatings under laboratory simulated high heat-flux and mechanical stress environments. It is also shown that the coating performance can be improved by utilizing advanced coating designs and hybrid coating processing, in conjunction with modeling and design tools to understand the coating lifing behavior. |