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Preparation and evaluation of silicon nitride matrices for silicon nitride-sic fiber composites. m.s. thesis final technical report
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Axelson, Scott R. |
| Copyright Year | 1988 |
| Description | Continuous silicon carbide (SiC) fiber was added to three types of silicon nitride (Si3N4) matrices. Efforts were aimed at producing a dense Si3N4 matrix from reaction-bonded silicon nitride (RBSN) by hot-isostatic-pressing (HIP) and pressureless sintering, and from Si3N4 powder by hot-pressing. The sintering additives utilized were chosen to allow for densification, while not causing severe degradation of the fiber. The ceramic microstructures were evaluated using scanning optical microscopy. Vickers indentation was used to determine the microhardness and fracture toughness values of the matrices. The RBSN matrices in this study did not reach more than 80 percent of theoretical density after sintering at various temperatures, pressures, and additive levels. Hot-pressing Si3N4 powder produced the highest density matrices; hardness and toughness values were within an order of magnitude of the best literature values. The best sintering aid composition chosen included Y2O3, SiO2, and Al2O3 or AlN. Photomicrographs demonstrate a significant reduction of fiber attack by this additive composition. |
| File Size | 2614859 |
| Page Count | 63 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19890014307 |
| Archival Resource Key | ark:/13960/t4pk58w6q |
| Language | English |
| Publisher Date | 1988-02-01 |
| Access Restriction | Open |
| Subject Keyword | Nonmetallic Materials Additives Ceramic Matrix Composites Densification Ceramic Fibers Hot Isostatic Pressing Silicon Carbides Fiber Composites Nitriding Microhardness Reaction Bonding Sintering Silicon Nitrides Fracture Strength Microstructure Matrix Materials Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Thesis |
