| About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
|
| Symposium
|
Manufacturing and Processing of Advanced Ceramic Materials
|
| Presentation Title |
Fabrication of Continuous Polycrystalline Silicon Nitride (Si3N4) Fibers via Powder Processing Route |
| Author(s) |
Hyunjun Kim, Michael Cinibulk, Lisa Rueschhoff, Randall Hay, William Costakis , Connor Wyckoff, Seamus McGarvey, Randall Corns, Kathryn Rutherford, Brian Sirn |
| On-Site Speaker (Planned) |
Hyunjun Kim |
| Abstract Scope |
Ceramic matrix composites (CMC) currently rely on Al2O3 and Al2O3/mullite oxide fibers in the NextelTM family produced by 3M, or SiC fibers produced by Japanese companies. These fibers are not optimal for CMCs for RF applications – the dielectric constant for SiC is too high and use temperatures for Nextel fibers are too low. Si3N4 has a dielectric constant of 7.5, and high temperature stability comparable to SiC. Introduction of porosity into the Si3N4 reduces its dielectric constant as low as 2.3. To compensate low strength of porous Si3N4, its fiber has been sought as a fiber reinforcement but Si3N4 fiber is not available commercially. AFRL/RXNC has developed processes for making polycrystalline YAG fibers and can easily adapt the processes for YAG fiber to prepare Si3N4 fibers. Detailed fabrication process of continuous polycrystalline Si3N4 fiber will be presented and its properties will be discussed. |