VAPOR-PHASE FORMATION OF MICRO-COILED CARBON-FIBERS USING NI CATALYST AND PH3 IMPURITY

Micro-coiled carbon fibres were prepared from the vapour phase via the catalytic pyrolysis of acetylene in the presence of Ni metal powder and a small amount of PH3. The effects of Ni and PH3 and of the reaction conditions and morphology on the growth of the coiled carbon fibres were examined. The P content in the Ni catalyst grain present at the tip part of the coiled carbon fibres increased with increasing reaction temperature and PH3 flow rate. The optimum P content was about 3 at.% in the Ni catalyst. The pre-phosphidizing of the Ni catalyst was not affected for the growth of the coiled carbon fibres and the yield significantly decreased, probably caused by the increase in the P content in the Ni grain of the tip.