| About this Abstract |
| Meeting |
MS&T21: Materials Science & Technology
|
| Symposium
|
Ceramic Matrix Composites
|
| Presentation Title |
Oxidation of BN Coatings in SiC/SiC Composites |
| Author(s) |
Victoria Christensen, Frank Zok |
| On-Site Speaker (Planned) |
Victoria Christensen |
| Abstract Scope |
Ceramic composites based on BN-coated SiC fibers and SiC matrices often exhibit property degradation at intermediate temperatures (600°C-1000°C). While it has been established that the degradation involves oxidation of the BN coatings, the mechanisms remain poorly understood. To address this challenge, oxidation experiments were performed on SiC/BN/SiC minicomposites in dry and wet air. Transverse and longitudinal sections through the oxidized specimens were characterized using scanning and transmission electron microscopy and x-ray dispersive spectroscopy. Complementary thermogravimetric analyses were performed on bare and coated fibers. The experimental results coupled with models of thermochemistry provide a means for understanding the time scales and environmental regimes over which the degradation mechanisms operate. |