连续还原碳化法制备纳米WC-Co复合粉研究

Preparation of nanophase WC-Co composite powder by continuing reduction carbonization

  • 摘要: 传统方法制备超细 WC-Co 混合料工艺过程复杂,制备的粉末成分及粒度分布不均匀,晶粒较粗,生产成本高.本研究采用连续还原碳化法,以偏钨酸铵 、醋酸钴 、热解碳源等为原料,在喷雾干燥、连续还原碳化系统中进行实验,对短流程制备工艺进行了探讨.通过喷雾结晶、低温还原碳化制备出纳米级 WC-Co 复合粉.研究结果表明:在 900 ℃温度下,碳化反应完全,制得的 WC-Co 复合粉晶粒度小于 100 nm.连续还原碳化法制备粉末的工艺流程短,易于实现产业化.

     

    Abstract: A traditional method for producing ultra fine WC -Co mixtures begins with tungsten oxides by calcination of APT. Tungsten powder is prepared in hydrogen by reducing. Carbon is then introduced, mixed, and carbonized to prepare WC. A wet -milling process is implemented with reduced Co powder. The WC -Co composite is obtained after drying process. The complexity and high cost of this method usually results in disqualified composition and particle size distribution. The obtained grain is not favorable for further refinement. For the purpose of industry application, a new method using ammonium metatungstate (AMT), so luble cobalt salt, and organic carbon source as raw materials to produce nanophase WC -Co composite powder is studied. In addition, spray drying, calcination, and a low temperature reduction carbonization process are required. The experiment results show that powder appearance is shell spherical skeleton structure. WC particles are coated by the Co molecule at the nano level with uniform component in molecular size. The particle size is in the range of under 100 nm. The powder has the character of good fluidity, fine crystal grain and even distribution.

     

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