Creep-resistant, high-strength silicon carbide fibers
US6187705A · kind A · utility
Inventor
Key dates
| Filing date | Nov 23, 1999 |
| Grant date | Feb 13, 2001 |
| Priority date | — |
| Expiry date | Nov 23, 2019 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B41/5346
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A high strength, high creep resistant, boron-doped, silicon carbon fiber having no boron nitride coating, originally formed by sintering, is produced by exposing the fiber to a nitrogen atmosphere at a temperature equal to or preferably elevated above the sintering temperature and also exposing the fiber to a carbon monoxide-containing atmosphere at a temperature sufficient to remove boron and boron nitride. The nitrogen atmosphere step may be performed before or after the carbon monoxide-containing atmosphere step. The resulting, uncoated SiC fibers have tensile strengths greater than approximately 2.0 GPa and Morscher-DiCarlo BSR test creep resistance M values greater than approximately 0.75 at 1400 degrees C for one hour in argon. The method is applicable to non-sintered fibers as well, in which case the nitrogen exposure is carried out at between approximately 1750 to 2250 degrees C and the carbon monoxide exposure is carried out at between approximately 1600 to 2200 degrees C.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.