Direct synthesis of nanocrystalline tungsten carbide from scheelite ore by solid state reaction method

This article reports the synthesis of nanocrystalline tungsten carbide by solid state reaction method directly from its ore. Scheelite-an ore of tungsten was milled for 50 h and 100 h with activated charcoal in excess of stoichiometric ratio followed by calcination in the argon atmosphere at different temperatures. The 100 h milled sample showed complete reduction/carburisation of scheelite at 1025 °C. The calcined sample was then acid washed (1:1 HCl) followed by base washing (0.25 M NaOH) to remove impurities and undesired reaction products. The obtained powders were characterised by X-ray diffraction, scanning electron microscope, HRSEM and HRTEM. The final product contained single phase nanocrystalline tungsten carbide (WC) phase. This method can be scaled up for bulk manufacturing of nancrystalline WC directly from ore.