A GROWTH-MECHANISM OF REGULARLY COILED CARBON-FIBERS THROUGH ACETYLENE PYROLYSIS

Regularly coiled carbon fibers were prepared by Ni catalytic pyrolysis of acetylene. A small amount of H2S was indispensable for the growth of the coiled carbon fibers. A Ni compound seed observed on the tip of the pair-coiled carbon fibers is a single crystal. It is suggested that each crystal plane of the Ni compound seed has a different catalytic ability for the growth of the coiled carbon fibers. A growth mechanism for the coiled carbon fibers called the "quasi-VLS mechanism" is proposed, which involves the surface diffusion of carbon species on the Ni compound seed.