Synthesis of ultrafine cubic tungsten carbide in a discharge plasma jet

Abstract

Hexagonal tungsten carbide (WC) is widely-used for the production of metal-working tools, but there is a great interest to the cubic modification of WC. The possibility of obtaining the ultrafine cubic tungsten carbide in an electrodischarge plasma jet generated by a high-current pulsed coaxial magnetoplasma accelerator is shown in this report. According to X-ray diffraction and high resolution transmission electron microscopy the product predominantly consists of a cubic tungsten carbide phase WC0.86 (95% mass). Lattice constant of obtained tungsten carbide is a=4.2536Å. This constant differs from the lattice constant (a=4.2355Å) for ICDD card no. 00-020-1316 (cubic WC1−x) nonetheless both of them are in the possible range for cubic tungsten carbide structures. The high cooling rate, realized in the system based on coaxial magnetoplasma accelerator, provides the formation of the cubic WC lattice and the narrow range of particle size distribution (10–40nm).