Growth mechanism for carbon nanotubes in a plasma evaporation process

Carbon nanotubes (CNTs) were synthesized through raw-material evaporation and condensation in RF thermal plasmas to investigate co-condensation process of the vapor mixture of carbon and metals. Addition of 10 wt.%-Ni was the most effective for the CNT synthesis, while Co, Fe, Mo, LaB6 had poor activity. These metal combinations presented synergy effect for the CNT formation. The combinations of Ni–Co, Ni–Fe, and Ni–LaB6 provided more effective activity in the CNT synthesis. Furthermore, the CNT growth mechanism from the vapor mixture of carbon and metals was discussed. Heterogeneous condensation model and carbon–metal molten model were selected as the CNT growth model.