Solid-state reaction synthesis of boron carbonitride nanotubes

Abstract

In this study, a simple route for synthesis of ternary boron carbonitride (B-C-N) nanotubes was demonstrated, by heating ball-milled mixture powders of amorphous boron and activated charcoal with a small amount of iron oxide (Fe(2)O(3)) at 1000-1200A degrees C under a mixture gas flow of nitrogen (N(2)) and hydrogen (H(2)). The reduction of Fe(2)O(3) by H(2) at 650A degrees C produced Fe nanoparticles, playing the role of a catalyst during the nanotube growth. The nanotubes synthesized at 1100A degrees C exhibit two morphologies. One is a bamboo-like structure with thick compartments. The other is a quasi-cylindrical structure with thin or disappearing compartments. The average diameter of the nanotubes is about 80 nm. It is found that the reaction temperature has a great influence on the morphology, diameter and yield of the B-C-N nanotubes. Higher temperature (1200A degrees C) is favorable for the formation of quasi-cylindrical nanotubes with larger diameters, while lower temperature (1000A degrees C) enhances the formation of bamboo-like nanotubes with smaller diameters; the yield of nanotubes decreases with the rise of reaction temperature. The nanotubes grow via a combination mechanism of solid-liquid-solid (SLS) and vapor-liquid-solid (VLS) models.