Synthesis of nanocrystalline boron carbide via a solvothermal reduction of CCl₄ in the presence of amorphous boron powder

Nanocrystalline boron carbide (B₄C) was synthesized via a solvothermal reduction of carbon tetrachloride using metallic lithium as reductant in the presence of amorphous boron powder at 600°C in an autoclave. The X-ray diffraction pattern of the product powder was indexed to the hexagonal B₄C phase, with lattice constants a = 5.606 and c = 12.089 A. The sample was also characterized by Raman spectrum, X-ray photoelectron spectroscopy and inductively coupled plasma atomic emission spectrometry. Transmission electron microscopy revealed that the B₄C nanocrystallites were slightly agglomerated, with a particle size of approximately 15-40 nm in diameter.