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

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.