silicon carbide fibres
(rus. волокна, карбидкремниевые)
—
structural fibre consisting of nanocrystalline silicon carbide.
Description
There are two methods of manufacturing silicon carbide fibres and, correspondingly, there are two types of such fibres. The first method is similar to the method of obtaining boron fibres – gas phase synthesis on a filament substrate. As a rule, a carbon filament with a diameter of 30-35 microns is used for this purpose. The density of fibres on the carbon filament is ~3.2 g/cm3, the average strength over the length of 25 mm is 3-4 GPa, the Young's modulus in the direction of the axis is ca. 420 GPa. The structure of SiC fibres is more stable at high temperatures than the structure of boron fibres, therefore they are used as reinforcing agents for titanium-based matrices (titanium alloys and Ti-Al intermetallic compounds).
The second method of producing silicon carbide fibres is based on pyrolysis of polycarbosilane filaments. The resulting fibres contain carbon and oxygen in addition to nanocrystalline silicon carbide; improvements in production of this type of fibres is aimed at reducing the content of those elements, which is accompanied by an enhancement of their mechanical characteristics. The main applications of these fibres are associated with the creation of SiC/SiC composites that demonstrate long-term operability at temperatures of up to 1,300°C.
The second method of producing silicon carbide fibres is based on pyrolysis of polycarbosilane filaments. The resulting fibres contain carbon and oxygen in addition to nanocrystalline silicon carbide; improvements in production of this type of fibres is aimed at reducing the content of those elements, which is accompanied by an enhancement of their mechanical characteristics. The main applications of these fibres are associated with the creation of SiC/SiC composites that demonstrate long-term operability at temperatures of up to 1,300°C.
Author
- Sergey T. Mileiko
Sources
- Concise Encyclopedia of Composite Materials / Ed. by A. Kelly. — Elsevier Science, 1994. — 378 p.
- Chawla K. K. Fibrous Materials. — Cambridge University Press, 1998. — 309 p.
- Handbook of Composites. V. 1: Strong Fibers / Ed. by W. Watt, B.V Petrov. — N.Y.: Elsevier, 1989.