Effect of Composition and Structure on the Specific Resistivity of Continuous Silicon Carbide Fibers

Three kinds of continuous SiC fibers with different specific resistivity were prepared by the pyrolysis of cured polycarbosilane fiber, and the structure and composition of the three fibers were characterized. Results show that SiC fibers with different specific resistivity can be obtained by changing the curing and pyrolysis conditions. And the total free carbon content and the ability to crystallize will no longer affect the specific resistivity notably when the fiber is covered with an excess carbon layer, as a result the fiber will have a low electrical resistivity. The excess carbon layer in the circular outer part is originated form the re-pyrolysis and deposition of hydrocarbon volatiles. Removal of the carbon by oxidative treatment may affect the surface property and also promote the mag- nitude of specific resistivity. The influence of the surface property on the specific resistivity is considerable which should not be neglected.