Preparation of carbon micro-coils with the application of outer and inner electromagnetic fields and bias voltage

The carbon micro-coils were prepared by the catalytic pyrolysis of acetylene at 770-775 degreesC using Ni, Nb, Ta and their oxides with the superimposed application of an electromagnetic field (AC, DC) from both the outer and inner sides of the reaction tube as well as with application of a bias voltage to the substrate. The effect of the electromagnetic field on the coil yield and morphology were examined. The coil yield increased by 1.1-1.2 times with the superimposed application of the AC or DC electromagnetic field. It was found that the superimposed application of the outer and inner electric magnetic fields resulted in the strong influence on the morphology of the grown carbon coils. The effect of the non-inductive zero magnetic field obtained with a counter magnetic field on the growth of the carbon coils was also examined. The maximum coil yield of 30-32.5 mg/cm(2)-substrate was obtained with the application of both the outer and inner DC-EM fields or non-inductive EM field. (C) 2002 Elsevier Science Ltd. All rights reserved.