Violet Tungsten Oxide Physical Properties

Violet tungsten oxide, abbreviated as VTO, is named after its purple appearance. It is the best raw material for the production of ultrafine or nanometer tungsten powder. It is produced in the process of precise control of temperature reduction and production of ammonium parotungstate.

The physical properties of violet tungsten oxide refers to the purple tungsten does not need to undergo chemical reactions or chemical changes to reflect some of the characteristics, such as appearance, grain size, specific surface area and density. Violet tungsten oxide has purple or blue purple fine-grained crystalline powder. Violet tungsten has unique crystal structure, and its particles are needle like or rod like, this structure has large gaps. The results show that in the process of hydrogen reduction, the morphology of violet tungsten oxide is acicular crystalline shape when the furnace temperature is too low. When the furnace temperature is higher, the morphology of violet tungsten oxide is a rod like crystal. Both needle and bar are the intrinsic crystal of purple tungsten oxide. Through the reduction test, we found that the tungsten powder made by needle shaped crystal violet tungsten oxide is finer, and the tungsten powder produced by the rod shaped violet tungsten oxide is relatively coarse.

Relative to blue tungsten oxide and yellow tungsten oxide, researchers found that the specific surface, average size and bulk density of violet tungsten oxide were the smallest. This superior physical property is favorable for the infiltration of hydrogen and the escape of water vapor during the reduction process, so that the reduction is not only initiated on the surface, but also can be carried out internally. So the chemical activity is the greatest, the fastest grain size is the fastest of the reduction of tungsten powder, and the quality of the cemented carbide is the best. In contrast, purple tungsten is suitable for making tungsten carbide precursor, but there is no good as blue tungsten oxide in the catalyst or other doped tungsten compounds.

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