PREPARATION OF MICRO-COILED CARBON-FIBERS BY METAL POWDER-ACTIVATED PYROLYSIS OF ACETYLENE CONTAINING A SMALL AMOUNT OF SULFUR-COMPOUNDS

Micro-coiled carbon fibres were prepared by the transition metal-activ ated pyrolysis of acetylene containing a small amount of sulphur compo unds, and the preparation conditions were examined in detail. The coil ed carbon fibres grew at the reaction temperatures of 700-850 degrees C and thiophene gas flow rates of 0.14-0.45 standard cm(3) min(-1) (0. 10-0.35 vol% reaction atmosphere). The optimum values depended on the type of metal catalysts used. Among the metal catalysts used, nickel, titanium and tungsten were the most effective for the growth of the co iled carbon fibres and a maximum yield of about 50%-55% was obtained. The bulk resistivity of the coiled carbon fibres decreased with increa sing bulk density and was 10(0) S-1 cm at a bulk density of 1.