C-and hollow shaped carbon fibers were prepared from heat-treated isotropic pitches through C-and hollow nozzles, respectively. The tensile strength and torsional rigidity of these fibers were studied with variation of shape factor, oxidation time, and CVD time. Tensile strength of the C-and hollow carbon fiber was affected by the oxidation time and the thickness of carbon fiber. The thinner the wall thickness of C-and hollow carbon fiber, the larger the tensile strength. On the other hand, the tensile strength of SiC-coated C-and hollow carbon fibers is decreased with increasing the CVD time, for the adhesion between fiber and coated layer become weak. The torsional rigidities of the C-and hollow carbon fibers were affected by the shape factor of carbon fiber, and the torsional regidities of the hollow shaped carbon fibers were higher than those of the C-shaped carbon fibers in the same shape factor. The torsional rigidity increased with increasing the CVD time, since the frequence of rotating shaft having SiC coated carbon fiber is increased.

C-and hollow shaped carbon fibers were prepared from heat-treated isotropic pitches through C-and hollow nozzles, respectively. The tensile strength and torsional rigidity of these fibers were studied with variation of shape factor, oxidation time, and CVD time. Tensile strength of the C-and hollow carbon fiber was affected by the oxidation time and the thickness of carbon fiber. The thinner the wall thickness of C-and hollow carbon fiber, the larger the tensile strength. On the other hand, the tensile strength of SiC-coated C-and hollow carbon fibers is decreased with increasing the CVD time, for the adhesion between fiber and coated layer become weak. The torsional rigidities of the C-and hollow carbon fibers were affected by the shape factor of carbon fiber, and the torsional regidities of the hollow shaped carbon fibers were higher than those of the C-shaped carbon fibers in the same shape factor. The torsional rigidity increased with increasing the CVD time, since the frequence of rotating shaft having SiC coated carbon fiber is increased.