Abstract
Nano carbon materials exhibit many unique properties and hence have enormous potential for industrial applications. Currently, all known fabrication methods were not able to accurately control the particle length. In this investigation, the Arc-Discharge Method have been developed with basic experimental setup being capable of not only fabricating the single-wall carbon tubes, multi-wall carbon tubes, and carbon onions automatically but also controlling the tube length. Moreover, a pulse generator and the associated control circuits for the servo motor have been employed for controlling the electric current, switching frequency, and current pulse-width during the fabrication process. As a further step, the Transmission Electron Microscope (TEM) was used for measuring the contents and compositions of the fabricated specimens. According to the experimental results, the carbon -tube length increases with time when the pulse current is set for constant. The controllable tube-length during fabrication process ranges from 50 to 700 nm. Stable nano particles have been obtained when the switching frequency of the plasma equipment is set at 250 Hz with duty cycle being at 0.25. The apparatus has performed precise electric current and electrode position control based upon the control parameter settings and would be useful for commercial uses in the future.