Published online by Cambridge University Press: 01 February 2011
A carbothermal reaction process was employed to synthesize nano-sized boron carbide particles. The reactions were carried out by heating a mixture of boric oxide powder and amorphous carbon reactant under a flow of argon atmosphere in a conventional high temperature tube furnace at 1350–1700 °C for 1–4 h. In order to obtain stoichiometric powder product, additional pure boron powder was added to the reaction mixture to compensate for the boron loss in the form of B2O2/B2O3 vapor during the reaction. The effect of the structure and morphology of the precursor materials on that of the products was also investigated. X-ray diffraction (XRD) studies indicated that the powdered product prepared under optimized reaction conditions was crystalline boron carbide. Transmission electron microscopy (TEM) observations showed that the product nanoparticles ranged from 50 nm to 250 nm with the average size between 100 nm and 150 nm depending on the reaction conditions. Some boron carbide particles were as small as 50 nm. Energy dispersive spectroscopy (EDS) was also used to determine the stoichiometry of the boron carbide nanoparticle products.