CHARACTERISTICS OF THE GRAPHITE ELECTRODE AS A PARAMETER FOR THE FORMATION OF SINGLE WALL CARBON NANOTUBES BY THE ARC METHOD

摘要

The electric arc method is now widely used to prepare single wall carbon nanotubes (SWNTs). Among the process parameters whose investigation was reported in literature, modifying the carbon electrode characteristics has been barely attempted. In addition, the effect of varying any parameter was rarely related to the physical modifications subsequently brought to the plasma The present communication reports the changes brought to the carbon phase typology and proportion which occuned in our arc reacts (vertical) while changing the fabrication method of the metal/carbon composite anode. One way (= homogeneous anode) was to use a pressureless sintering method, resulting in a homogeneous dispersion of Ni-Co alloy catalyst particles (30-200 nm in size) into a graphitic carbon electrode (samples Test#2 and Test#3). The other way (= standard anode) was to use a mixture of catalyst powders (Ni and Co, or Ni and Y, < 400μm) and graphite powder, stuffed into a hole drilled in the middle of agraphite electrode~2 (samples Montp-1 and Montp-2). Other results obtained from changing the catalysts (Ni + Y instead of Ni + Co) and the pressure value (420 instead of 650 mbars) are also reported.