Improvement of Mechanical and Micro structural Behavior of Graphite Disc after Plasma Treatment
Abstract
Carbon nanotubes (CNTs) successfully developed in graphite disc only after 5 min of thermal arc plasma treatment under argon atmosphere. Plasma treatment was carried out in an innovatively designed 50 kW plasma reactor. Graphite sample was treated at voltage: 60 V-70 V and current 250 A-300 A. Electrical power consumed for the preparation of CNTs was in the range of 15-21 kW. Various characterization techniques such as x-ray diffraction, energy dispersive spectra of X-ray, micro Raman spectroscopy, transmission electron microscopy, field effect scanning electron microscopy, BET surface area measurement and electrical conductivity were employed to evaluate the properties of samples. Raman spectra show different peaks of C such as D, G and 2D. Field emission scanning electron microscopy of graphite revealed vertical grows of MWCNT filaments in form of spheroids. EDS shows the presence of only C phase. Transmission electron microscope confirms the grow of MWCNT (multiwall carbon nanotubes). Electrical conductivity of the graphite disc after plasma treatment by 21 kW power showed significant increase in conductivity (40 ×103 S/m) in comparison to that of pure graphite. While BET surface area of the untreated graphite was found to be 8 m2g-1, the plasma treated graphite prepared by 21 kW power showed the surface area to be 1240 m2g-1. Plasma treated graphite (prepared by 21 kW) shows around 50 times more micro hardness value than untreated graphite.
