交流放电法合成多种形态的碳纳米管

碳纳米管的发现［１］引起了科学界的广泛重视，人们对于这种新型材料在纳米导线、高强纤维、超导等方面的应用寄予厚望．目前，合成碳纳米管的方法主要是采用不等径石墨棒直流放电，在阴极上得到含有碳纳米管的沉积物［２］．对于碳纳米管的应用，有关的理论研究［３］及...

Production of Various Forms of Nanotubes by AC Arc Discharge

Various forms of nanotubes were produced by AC arc discharge method at a low He pressure. Because the two graphite electrodes we used have the same diameter, there was no deposit formed on the end of the cathode. This is a significant difference from the conventional DC method used to form carbon nanotubes. Some forms of nanotubes different from those reported were found in the soot(but not the cathode deposit). They were the carbon nanocapsule, carbon cone shaped nanotube and the carbon toroidal nanotube. The nanocapsule has a length diameter ratio below the conventional nanotubes. The cone nanotube has a cone shape. The toroidal nanotube has a shape like a tire. These novel products were found in the soot. Their formation may arise from the periodic alternantion of the current we used. The difference of the formation mechanisms between AC arc discharge and DC arc discharge were discussed.