Superfine crystal tungsten carbide has excellent performances, which is widely used in industrial field. Ultrafine crystal tungsten carbide can be prepared by spray-drying process, of which the main material is mainly superfine WC-Co composite powder. Spray-drying process is a widely applied technology to prepare ultrafine WC-Co composite powder at present. It is also the main way to produce ultrafine WC-Co powder at present.

 

 

Spray-drying process with the principle of thermo chemical synthesis can synthesize ultrafine WC-Co composite powders by thermochemistry of water-soluble precursors. At the same time, the particle size of the obtained powder can be controlled in a wide range, that is, it can be controlled between nanometers and micrometers.

 

The method is suitable for mass production, as the process is simple and other impurities will not be introduced. During the process, the control of the reduction process of the powder precursor is very important.

 

Technology Path:

1, The aqueous solution of precursor compounds is prepared first, usually using ammonium tungstate, cobalt chloride or cobalt nitrate or cobalt oxalate as precursor compound water solution.

 

2, Amorphous precursor powder is obtained by spray drying of the initial solution.

 

3, The precursor powder is converted into ultrafine WC-Co powder in fluidized bed by H₂ reduction and CO/CO₂ as carbon source.

 

Process Characteristics:

1, The presoma can be uniformly dispersed in the form of liquid phase, and W and Co chemical components can be uniformly dispersed at molecular level, so as to facilitate the addition of grain growth inhibitors, so that WC grain growth can be controlled during sintering.

 

2, Spray-drying process can be used to prepare superfine oxide composite powder first and provide early guarantee for the preparation of superfine powder by carbon heat reaction in the next step.

 

3, Closed production system reduces the waste of materials and the pollution of the environment.

 

4, Because of the long carbonation time which is over 10 hours, the grain size is easy to be coarsely coarsened, which makes the grain degree more difficult to control.