Tuesday, November 07, 2006

US Patent 7132039 - Magnetic Field Assisted Nanotube Fabrication


One of the main ways used to manufacture carbon nanotubes is the arc discharge method in which a high voltage potental is applied between graphite electrodes in an inert gas environment. However, impurity is often found in the nanotubes made in this fashion. This patent is based on the discovery that magnetic fields can increase the resultant purity. Claim 1 reads:

1. An apparatus for manufacturing a carbon nanotube, comprising: at least two electrodes whose tips oppose to each other; a power supply which applies a voltage between the electrodes so as to generate discharge plasma in a discharge area between the electrodes; a plurality of magnets which generates at least one of a magnetic field of multiple directions and a magnetic field having a component in parallel with the direction of a discharge current in the generation area of the discharge plasma; and a magnet cooling unit which cools the magnets.