Carbon nanotubes on SiC powder surface grown by a vacuum heating process

Silicon carbide (SiC) powders were baked on a resistively heated tungsten (W) boat at 1,600-1,700 degrees C for 10-15 min in vacuum. The surface morphology of the treated SiC powders was observed using a high resolution scanning electron microscope (HR-SEM). Carbon nanotubes were observed on the surface of 40% of SiC powder. The nanotubes were dense, but slightly dispersed and their growth direction was almost perpendicular to the original surface. The nanotubes on SiC were considerably shorter than that prepared by carbon are method, but significantly longer than that prepared by laser sublimation of SiC. Energy dispersive X-ray spectrometory (EDX) analysis suggested that W and O were doped on or in the vicinity of the powder surface.