PREPARATION AND PROPERTIES OF COILED CARBON-FIBERS BY THE CATALYTIC PYROLYSIS OF ACETYLENE

Microcoiled carbon fibers were obtained by the Ni catalyzed pyrolysis of acetylene at 600-800-degrees-C. The presence of small amounts of a sulfur compound impurity was indispensable for the growth of the coile d carbon fibers in high yield with good reproducibility. The optimum g rowth temperature was 750-degrees-C irrespective of the kind of sulfur compounds used as the impurity. The optimum impurity gas flow rate wa s restricted to a very narrow range depending on the impurity type. Th e maximum yield (about 50 %) of the coiled carbon fibers was obtained using thiophene. Some properties of the coiled carbon fibers were exam ined. A new growth mechanism for the coiled carbon fibers will be pres ented.