Fine tungsten powder used more widely, it also makes the study of ultrafine tungsten powder is increasing. Currently the producing method of ultrafine tungsten powder has three main research directions: First, to improve the blue tungsten process. Second, the introduction of new reduction methods, such as hydrogen halide reduction and the third is the use of laser and other new fluidized technology. The study found that using violet tungsten oxide to producing fine particles of tungsten powder is good than using blue tungsten oxide so the producing fine particles of tungsten powder the violet tungsten as material is more popular than blue tungsten oxide. But violet tungsten powder particle sizes also will influent tungsten powder size and properties. Fine violet tungsten powder can produce good properties fine particles so to produce fine particles violet tungsten oxide has a certain significance and role for fine tungsten powder. Producing process as follows:
1. The amount of APT loaded boa then push into hot zone of reduction furnace, while feeding a certain proportion of mixed gas which is hydrogen and water vapor, heated to a predetermined temperature to cool for a while after being room temperature draw a charge
2. In the heating, keeping, cooling process, the gas flow rate remains constant.
3. Using WLP202 type fsss analyzer to analysis raw material and product and the phase of the product analysis by the x-ray diffraction.

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Violet tungsten oxide (VTO) restore to tungsten powder in the first and second redox reactions the particle size of these two reduction has not big different.

Continue to analyze the third redox reaction found the third time tungsten trioxide restore to tungsten powder and the specific surface area of it is 1.082 m² • g^-1 in the third time reaction which is the 6.56 times to second reduction tungsten powder’s specific surface area. Apparently,   third reduction tungsten powder particle size is very small, and most concentrated in the 0.21-1.05um, but there is significant agglomeration, so that the measured particle size is agglomeration but not tungsten powder. According oxidation - reduction mechanism shows that the majority of the oxide reduction process is carried out simultaneously, but some tungsten oxide first reaction and others after reaction then the after reaction tungsten powder will cover in the first reaction tungsten powder so the tungsten powder particle size will group up, so that the tungsten powder particle size distribution is relatively concentrated and uniform.

VTO after third times reduction and second time oxidation can produce submicron tungsten powder particle size between 0.21-1.05um and specific surface area is 1.082 m² • g^-1 which has not coarse particle. 

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Nano tungsten powder is widely used in modern industry and science area, so good performance nano tungsten powder can improve application in the field of modern industry and science which has great significance. But good properties nano tungsten powder producing requirements is quite high. The violet tungsten oxide (VTO) has different properties with other tungsten oxides. It is the most suitable material for produce nano powder, so using VTO as material producing nano tungsten powder not only the tungsten powder has good performance and the process is relatively simple. But in order to producing good properties tungsten oxide in addition to control the raw martial but also need to control the production process which is temperature, push boat speed and the amount of hydrogen, only in gentle heating process, moderate reaction, smooth gas migration so can effectively control the water vapor to escape which is an important factor for producing good properties nano tungsten powder.

By controlling the raw materials and process conditions the nano tungsten powder has high purity and crystallinit as well as has stable properties and loose structure. What’s more the appearance of it is sphere and distribution uniform which has large specific surface area, pore structure simple.

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After analyzing tungsten powder which restore from violet tungsten oxide for first time researcher found tungsten powder particle size are smaller and more uniform, but has reunion phenomenon.

Then the researcher analysis the second redox reaction found tungsten trioxide restore to tungsten powder in hydrogen and the specific surface area of tungsten powder is 0.165m² • g^-1 which is the1.71 times to first reduction tungsten powder’s specific surface area. From this data analysis the researchers found comparison the first time and the second time reaction of tungsten powder particle size they didn’t have large different. The second reduction tungsten oxide particle size is mainly between 4.24 and 11.11um, centralized distribution and uniform.

The tungsten powder in the air second oxidize to tungsten trioxide and the specific surface area of it is 0.719 m² • g^-1, is the 4.96 times to first oxidized tungsten trioxide’s specific surface area which is more finer than first time but the distribution is very scattered and not concentrated area. This is mainly because the tungsten trioxide has significant agglomeration, the particle size which measuring is agglomeration not the tungsten trioxide particles.

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