synthesis and purification of carbon nanotubes

in this study, multi wall carbon nanotubes (mwcnts) were synthesized by chemical vapor deposition (cvd) method using two different catalysts (fe nanoparticles) and (ni nanoparticles) with  two different substrates: quartz and alumina. acetylene gas was used as a carbon source and argon as a carrier gas at different temperatures and different times to study the effects of these parameters on cnts yield. the produced mwcnts were then purified by oxidation followed by chemical method involving treatment of mwcnts with concentrated acids (h2so4 and hno3) to remove impurities. the mwcnts were then functionalized by acidic treatment. the functionalized mwcnts were then coated with nickel using electroless plating method. metal matrix composites (mmcs) were prepared by powder metallurgy method using al/uncoated mwcnts and al/coated mwcnts. the results show that the diameter range of prepared mwcnts was (30-50) nm. the yield of cnts using ni nanoparticles as catalyst is higher than that of using fe nanoparticles as catalyst. the coated cnts have diameters ranging from 65-85 nm. the hardness of al/coated cnts composites is higher than that of al/uncoated mwcnts composites.