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How To Prepare Spherical Tungsten Powder

2018-9-5      View:

With the rapid development of technologies such as 3D printing technology, porous materials, high-density powder coating and injection molding, the demand for high-quality spherical tungsten powder is increasing. The high-quality spherical tungsten powder not only has good fluidity, good sphericity, high bulk density and tap density, but also low oxygen content.

                                                  

 

The process of reducing tungsten oxide by hydrogen to produce spherical tungsten powder requires a large amount of hydrogen and a high production cost. The main characteristics of the tungsten powder prepared by the halogenation method are high purity, fine particles, uniform particle size, spherical particles and high thermal stability. However, since tungsten powder is prepared by reduction of tungsten halogenated hydrogen, a highly corrosive hydrogen halide gas is involved in the reaction, and the working conditions are not bad, which not only causes environmental pollution but also corrodes production equipment, so this method is rarely used at present.

 

Concentrated sulfuric acid is used as a precipitant and dispersant of ammonium tungstate to obtain a tungstic acid precipitate, and then the precipitate is dried and hydrogen-reduced to obtain a spherical tungsten powder, this method has a significant effect on the grain size refinement of tungsten powder, and can get spherical tungsten powder, however, there are problems such as high production cost, high number of processes, low metal yield and disposal of waste liquid, which limits the industrial application of the method.

 

Because the plasma has the characteristics of high temperature, high enthalpy, high chemical reaction activity, reaction atmosphere and controllable reaction temperature, it is very suitable for preparing spherical powder with high purity, small particle size and uniform particle size distribution. For example, MORIYSOHI of Hosei University in Japan conducted a study on the production of ultrafine spherical tungsten powder by a mixed plasma composed of high-frequency plasma and direct current plasma to produce spherical tungsten powder having an average particle diameter of 10 nm.

 

At present, the spherical tungsten powder prepared in China still has the disadvantages of wide particle size distribution range, low solid yield and high cost. The research and development of spherical tungsten powder is still in the development stage, the preparation process, technology and process have yet to be further studied. There is still a certain distance from the realization of industrial production.