Carbon nanotubes on electrodes in short-time heteroelectrode arc

Short-time arc discharges with a short gap were generated between heteroelectrodes in stationary and running arc mode, under 25 kP of He. The electrodes used were pure graphite (C), nickel and yttrium mixed graphite (C–Ni/Y), and molybdenum (Mo). After the arc discharge, the surfaces of the anode and cathode were microscopically observed. On Mo electrode surface, no nanotubes were observed. With regard to C electrode, the multiwall nanotubes were observed only at the cathode spot where the arc was forcibly extinguished, and no nanotubes were observed at the anode spot. On the other hand, when the C–Ni/Y was used for the electrode, the nanotubes were observed both at the cathode spot where the arc was forcibly extinguished, and at the anode spot. These nanotubes on C–Ni/Y electrode were of multiwall, not of single wall.