The growth of various carbon phases composed of the nano-sized carbon particles (multiwalled carbon nanotubes, nanofibers, nanocrystallites, etc) on rolled Ni substrates from the methane precursor was studied using a Plackett–Burman saturated experimental design. The effect of various CVD synthesis parameters on the yield of carbon phases and on the size of the nanocrystallites was evaluated. It was established that the Ni catalyst exhibits an insignificant activity towards the formation of the extraneous glassy carbon phase. Meanwhile, this parameter is active in formation of the carbon phases containing nano-sized particles. The use of additives (ammonia, water and / or acetone) in the methane precursor can considerably affect the yield of various carbon phases in the CVD process. All these additives increase the production of carbon nanofilaments. Inorganic components (ammonia and water) suppress the formation of glassy carbon phase, while the organic component (acetone) increases the yield of glassy carbon. Moreover, ammonia is a component that can be considered as the most effective among the other parameters in reducing the crystallite size.

Keywords: carbon nanotubes, nanofibers, experimental design, CVD