| About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
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| Symposium
|
Advances in High-Temperature Oxidation and Degradation of Materials for Harsh Environments: A SMD and FMD Symposium Honoring Brian Gleeson
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| Presentation Title |
Si Bond Coat Oxidation in SiC-Composite Yb2Si2O7 Systems |
| Author(s) |
Rachel Guarriello, Dominic Pinnisi, Elizabeth Opila |
| On-Site Speaker (Planned) |
Elizabeth Opila |
| Abstract Scope |
SiC-based ceramic matrix composite (CMC) coupons were coated with a silicon bond coat and a Yb2Si2O7 environmental barrier coating (EBC) using atmospheric plasma spraying. CMC coupons were oxidized at 900, 1050, and 1200°C in 4.4 atmosphere dry oxygen for 500h at nearly stagnant conditions (5 x 10-4 m/s) to explore thermally grown oxide (TGO) formation on the silicon bond coat. The observed TGOs formed thoughout the bond coat at splat boundaries making quantification of oxidation rates difficult. Image analysis was used to determine the fraction and distribution of TGO in the bond coat. It was found that after 900°C exposures, the TGO was distributed through the bond coat consistent with a diffusion profile, whereas after exposures at 1050 and 1200°C, the TGO was concentrated at the EBC–bond coat interface establishing a barrier layer for further transport of oxygen through the bond coat. Implications for CMC/EBC life will be discussed. |