Carbon fibers are successfully grown on ceramic and/or graphite substrates through thermal decomposition of vaporized hydrocarbons such as benzene, benzine and toluene at temperatures from 1 100°C to 1300°C.The diameter ranges from 3 to 300μ and the length about 10 to 25 cm. Appropriate conditions for the growth of such long fibers are described. Some branched and crossed structures were observed in the fibers.Morphological and structural studies are made by means of optical microscope, scanning electron microscope, electron diffraction and X-ray diffraction. It is concluded that these carbon fibers are composed of cylindrical layers and scrolls of thin aromatic films aligned parallel to the fiber axis.There are two kinds of fibers with smooth and rough surface as shown in the accompanying photographs. The electrical resistivity, the tensile strength, the Young's modulus and the elongation are found to be 12×10
-3 ohm-cm, 434ton/cm
2, 24×10
3 ton/cm
2 and 0.3∼0.7% respectively.
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