The Role of Carbon Source in the Production of WC Powders

Tungsten carbide powders are typically produced either by carburization of tungsten metal powders (W) or by carbothermal reduction of tungsten oxide powders (WO3). Different powders can be used as carburizing source like carbon black and graphite. Synthesis of nanostructured WC powders is achieved by a two-step process: mechanical activation of initial powders (by milling), followed by thermal activation of mixes. The properties and microstructure of the resulting tungsten carbide powders (WC) can be influenced both by the raw materials and by the mixing /carburization process (temperature and atmosphere). This work presents a review of the studies carried out with several different graphite and carbon black powders for synthetizing nanosized WC from both W and WO3 powders. It is shown how the effectiveness of the mixing/carburization process for synthesis of nanostructured tungsten carbide powders is importantly affected by the type of carbon source used