About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
|
| Symposium
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Advanced Manufacturing of High Temperature Ceramics and Composites: Processing, Characterization and Testing
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| Presentation Title |
Synthesis and Characterization of Next-Generation Multiphase Silicon Nitride-Based Structural Ceramics |
| Author(s) |
Katherine Ann Brizzolara, Stephen DiPietro, Mark Opeka, Curtis Martin, Kevin Hemker |
| On-Site Speaker (Planned) |
Katherine Ann Brizzolara |
| Abstract Scope |
Structural ceramics for use in extreme environments must possess a broad suite of properties. The current study was undertaken to show the multi-phase Si<sub>2</sub>ON<sub>2</sub>/Si<sub>3</sub>N<sub>4</sub>/SiO<sub>2</sub>/BN ceramics can be produced using a novel two-step, near-atmospheric pressure processing technique. Nitridation of Si, SiO<sub>2</sub> and BN yielded ceramics with α-Si<sub>3</sub>N<sub>4</sub> and then β-Si<sub>3</sub>N<sub>4</sub>, while maintaining BN in the matrix. We will contrast nitridation of Si<sub>3</sub>N<sub>4</sub> from silicon powder versus a combination of silicon and silica powders. Calcining the product in a gas pressure sintering furnace can lead to Si<sub>2</sub>ON<sub>2</sub>, which can present an elongated grain morphology and may improve mechanical properties. The microstructural details of Si<sub>2</sub>ON<sub>2</sub> nucleation and growth are not well understood and are a major focus of this study. The plate-like BN grains further improve the toughness of the overall composite. Moreover, processing multi-phase ceramics in this manner eliminates the need for hot isostatic pressing and facilitates lower cost, near-net shape processing. |