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The role of carbon source in the production of ultrafine and nanocrystalline WC-6Co cemented carbides

  • : Raffaele Gilardi1, Luigi Alzati1, Raquel de Oro Calderon2, Eduard Hryha3, Lars Nyborg3, Sigurd Berg4
  • : 1Imerys Graphite & Carbon, 2Technical University of Vienna, 3Chalmers University of Technology, 4Höganäs Sweden AB, 5Sigmacarb S.A.
  • : PDF Download
  • : 2015

Abstract

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. The development of efficient production processes for obtaining ultrafine and nanocrystalline WC powders can promote a significant improvement in mechanical properties of WC-based hard materials. 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 conditions (temperature and atmosphere).

This work presents the effect of the carbon source reactivity (synthetic graphite and different carbon black types) on the synthesis of nanocrystalline WC powders and ultrafine WC-6Co cemented carbides. This experimental work sets the basis for optimizing the production of nano-WC powders based on raw material selection and process conditions.

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