METHOD OF PREPARING TUNGSTEN CARBIDE AND TUNGSTEN CARBIDE PREPARED BY THIS METHOD Russian patent published in 2003 - IPC

FIELD: nonferrous metallurgy. SUBSTANCE: invention can be used for preparing hard alloys, protective high-temperature, erosion-resistant, and emission coatings. Exothermic portion is prepared by blending, wt %: WO₃ 24.6, Mg 23, carbon black 2,4, and recycled synthesis product or NH₄Cl, or MgO, or polystyrene, or polyethylene 35-40, amount of carbon black constituting no larger than 50% stoichiometric excess with regard to WO₃. Resulting blend is placed into reactor, the latter is filled with argon to pressure at least 0.5 MPa and sealed, after which contents are inflamed. When burning stops, reactor is cooled, synthesis product is successively treated with 5-10% sulfuric acid, 5% chromic mixture, washed with water, and dried. Product, after acidic treatment, can be additionally treated with NaOH and KOH solution with concentration at most 2.5%. Tungsten carbide thus obtained represents micro-powder with hexagonal modification characterized by major particle size 0.1-0.2 mcm (natural cut), content of impurities no more than 0.1 wt %, including free carbon no more than 0.05 wt %. Natural cut is expressed by particles with regular hexagonal and rhombohedral forms, splices and druses with sharp facets and angles. EFFECT: improved physical characteristics of product. 7 cl, 4 ex