Journal of Minerals and Materials Characterization and Engineering, 2012, 11, 961-964
Published Online October 2012 (http://www.SciRP.org/journal/jmmce)
Optimization of Electrical Parameters for Production of
Carbon Nanotubes
Sayantan Chattopadhyay, Kalyan Kumar Singh
Department of Mechanical Engineering & Mining Machinery Engineering Indian School of Mines (ISM), Dhanbad, India
Email: sayantanchattopadhyay@ymail.com
Received July 20, 2012; revised August 22, 2012; accepted August 30, 2012
ABSTRACT
For more than two decades, there had been extensive research on the production of carbon nanotubes (CNT) and opti-
mization of its manufacture for the industrial applications. It is believed that they are the strong enough but most flexi-
ble materials known to mankind. They have potential to take part in new nanofabricated materials. It is known that,
carbon nanotubes could behave as the ultimate one-dimensional material with remarkable mechanical properties. More-
over, carbon nanotubes exhibit strong electrical and thermal conducting properties. In the process of optimizing the
production in line with the industrial application, the researchers have found a new material to act as an anode i.e. coal,
which is inexpensive as compared to graphite. There are various methods such as arc discharge, laser ablation, chemical
vapour deposition (CVD), template-directed synthesis and the use of the growth of CNTs in the presence of catalyst
particles. The production of carbon nanotubes in large quantities is possible with inexpensive coal as the starting carbon
source by the arc discharge technique. It is found that a large amount of carbon nanotubes of good quality can be ob-
tained in the cathode deposits in which carbon nanotubes are present in nest-like bundles. This paper primarily concen-
trates on the optimising such parameters related to the mass production of the product. It has been shown through Sim-
plex process that based on the cost of the SWNT obtained by the arc discharge technique, the voltage and the current
should lie in the range of 30 - 42 V and 49 - 66 A respectively. Any combination above the given values will lead to a
power consumption cost beyond the final product cost, in turn leading to infeasibility of the process.
Keywords: Coal; Carbon Nanotubes; SWCNT; Simplex; Optimization
1. Introduction
In 1985, Drexler proposed a molecular bearing consisting
of two graphitic nanotubes of different diameter, which
are concentrically arranged. It was a virtual operation
inside a computer. This dream, however, has become
more realistic by the discovery of carbon nanotubes.
There had been revolutionizing researches on the pro-
duction of Carbon Nanotubes from last twenty years and
optimising its manufacture for the industrial applications.
It has been thought that they are the strongest but most
agile materials known to humankind, and thus have po-
tential to take part in new nanofabricated materials as
additives. It has been shown that carbon nanotubes could
behave as the ultimate one-dimensional material with
remarkable mechanical properties. Carbon nanotubes ex-
hibit strong electrical and thermal conducting properties.
Study of the past researches on the production of carbon
nanotubes from coal revealed that most of the researches
concentrate on producing CNT by arcing electrodes,
produced separately by mixing the crushed coal with coal
tar followed by molding process. However, the only
process till date that has shown a positive adaptation to
direct coal application is thermal plasma jet technique.
With the extensive research in the production of the
Carbon Nanotubes, the requirement of optimising the
process parameters are realised. This paper concentrates
on the optimising such parameters related to the mass
production of the product. It has been found through cal-
culation that the only determining parameter in the arc
discharge technique is the power of the equipment, in
terms of voltage and current, and it is seen that on opti-
misation of these parameters, the cost of the process re-
duces drastically.
2. CNT Production through Arc Discharge
Technique
Carbon nanotubes (CNTs) have been used in various
fields of research due to their unique properties. There
are various methods such as arc discharge, laser ablation,
chemical vapour deposition (CVD), template-directed
synthesis and the use of the growth of CNTs in the pre-
sence of catalyst particles [1]. Special ambient gas is re-
quired for the fabrication of CNTs, in order to prevent
the oxidation of carbon at high temperature.
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