Effect of composition and structure on specific resistivity of SiC fibers
(State Key Laboratory of Novel Ceramic Fibers and Composites, National University of Defense Technology,
Changsha 410073, China)
Changsha 410073, China)
Abstract: Four kinds of SiC fibers with different specific resistivities were prepared by the pyrolysis of cured polycarbosilane fiber. The results show that SiC fibers with different specific resistivities can be obtained by changing the curing and pyrolysis conditions. And the free carbon content and the ability to crystallize no longer affect the specific resistivities notably with the time when the fiber is covered with an excess carbon layer, and the fiber has a low specific resistivity. The excess carbon layer in the circular outer part is originated from the re-pyrolysis and deposition of hydrocarbon volatiles. The removal of the carbon by oxidative treatment may affect the surface property and also promote the magnitude of specific resistivity. The influence of the surface property on the specific resistivity can be considerable and should not be neglected.
Key words: silicon carbide fiber; excess carbon layer; specific resistivity