| About this Abstract |
| Meeting |
MS&T21: Materials Science & Technology
|
| Symposium
|
Coatings to Protect Materials from Extreme Environments
|
| Presentation Title |
Effects of Topcoat Modifications on Bond Coat Oxidation, Internal Stresses, and Interface Toughness in Multilayer Si/Yb2Si2O7 Environmental Barrier Coatings |
| Author(s) |
Benjamin R. Herren, Chihpin Chuang, Jonathan D Almer, Kang N Lee, Katherine T Faber |
| On-Site Speaker (Planned) |
Benjamin R. Herren |
| Abstract Scope |
In Environmental Barrier Coating (EBC) systems exposed to high-temperature combustion environments, progressive bondcoat oxidation results in mismatched material properties, internal strains, and ultimately topcoat spallation. Limiting bondcoat oxide growth is thus expected to increase EBC reliability and lifespan. This study examines the effects of modifying topcoat composition on oxide growth and internal stresses in a current (Si/Yb2Si2O7) EBC. Steam cycling simulated the humid, high-temperature engine exposures and was used to assess the compositional effects on thermal oxide thickness, microstructure, and chemistry. Nanoindentation was used to evaluate interface toughness changes with composition and exposure. Synchrotron X-ray scattering and imaging permitted observation of internal strains and damage. By comparing internal strains, associated stresses, microstructure, and interface toughness between modified and baseline EBCs, the influence of topcoat composition and thickness modifications on EBC longevity may be discerned. |