Abstract
Carbon fibers are successfully grown on ceramic and/or graphite substrates through thermal decomposition of vaporized hydrocarbons at temperatures from 1100°C to 1300°C. The diameter ranges from 3 to 100 µm and the length 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, and X-ray diffraction. It leads to a conclusion 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 surfaces as illustrated in the accompanying photographs. The electrical resistivity, the tensile strength and the Young's modulus are found to be 1–2×10-3 ton-cm2, 4–34 ton/cm2 and 2–4×103 ton/cm2 respectively.