Carbon Nanofibers Synthesized by Glow-Arc High-Frequency Discharge

Carbon nanofibers (CNFs) have been successfully synthesized by an ac glow-arc discharge in a $\hbox{He}{-}\hbox{CH}_{4}$ mixture gas with 34%at.Ni/10.32%at.Y as catalyst under high frequency (42 kHz) and low power supply (360 W). This method profits the particle agglomeration in the gap under the influence of high-frequency electrical field. The power density in the plasma region is inferior to 0.1 $\hbox{W/cm}^{3}$ and the processes time duration is lower than 5 min. Results obtained from scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Raman scattering show that CNF are relatively free of amorphous-carbon coating. Surface and structural analysis indicate that the CNFs have an average diameter of 80 nm.