Tungsten Oxide

Tungsten powder is the basic raw material for making cemented carbide. Most of the cemented carbides in the market do not have much demand for the size of tungsten powder, but they have strict requirements for the particle size uniformity of tungsten powder. A new method of ammonium tungstate cyclic oxidation reduction method proposed in recent years for producing submicron tungsten powder, it is mainly through a number of ammonium tungstate - tungsten oxide circulation change, submicron tungsten powder and ultimately the average particle size. Therefore, we can also try to use circulating oxidation reduction method to help the common tungsten powder to achieve particle size rebalancing. It is necessary to prepare blue tungsten for reduction of tungsten powder because of the preparation of ordinary particle grade tungsten powder. The general process of ammonium tungstate cycle oxidation reduction method is: the special pure ammonium paratungstate in argon to slowly raise the temperatur...

The properties of tungsten powder s may be seriously affected by the third element. In production, these characteristics can be used to add third elements to control the particle size of tungsten powder to produce some special kinds of tungsten oxide. This method is called doping. When doped, the tungsten oxide is added to the aqueous solution of the element compound. The most suitable for doping is not yellow tungsten nor purple tungsten, but blue tungsten. The commonly doped elements are sodium, lithium, chromium, and rare earth elements. 1. Sodium-doped: The addition of sodium compounds is a common method in preparing coarse tungsten powders, the amount of sodium is usually between 50-200 and m/g. At 1000°C under wet hydrogen conditions, tungsten powders with an average particle size of 10-25 um can be obtained according to the thickness of the material layer, high temperature ensures strong volatilization of sodium at the end of the reduction process, it is ...

In addition to the blue tungsten oxide form affects tungsten powder particle size, the process parameters also affect the size of tungsten powder. Influence of process parameters on the tungsten powder particle size is mainly hydrogen mode, heating systems and hydrogen influence humidity. There are two kinds of hydrogen modes, one is cis hydrogen mode and the other is inverse hydrogen. The study found that cis hydrogen mode reduction of tungsten powder particle size is significantly thinner than the inverse hydrogen mode. ATB phase blue tungsten powder at low temperature with cis hydrogen mode can producing tungsten powder particle size thinner, narrow distribution, and the nature the better.  In heating system, the researchers found that heating from a low temperature and the heating process more gentle process are good for the producing fine tungsten powder. At the same time hydrogen humidity also impact on the tungsten powder particle size, at the same other proces...