What Is The Difference Between Blue Tungsten And Violet Tungsten?

As a typical representative of oxygen-vacancy/oxygen-deficient tungsten oxide, blue tungsten oxide (blue tungsten) and purple tungsten oxide (purple tungsten) are composed of +6-valence tungsten (W6+), +5-valence tungsten (W5+) ) and a tungsten oxide composed of -2-valent oxygen element (O2-), but they have certain differences in particle size, particle morphology, physical and chemical properties, and production processes.

(1) Conceptual aspects

Blue Tungsten Oxide (BTO) is a compound composed of 20 tungsten atoms and 58 oxygen atoms. It is composed of ammonium tungsten bronze (ATB), hydrogen tungsten bronze, β-tungsten oxide, and γ-tungsten oxide. A mixture; is a light or dark blue powder with the formula W20O58 or WO2.90.

Violet Tungsten Oxide (VTO or TVO) is a compound composed of 18 tungsten atoms and 49 oxygen atoms. It is a finely divided purple powder crystal with the chemical formula W18O49 or WO2.72.

(2) Microstructure

Under the same factors such as raw materials and production process, although both blue tungsten and purple tungsten particles maintain the appearance of ammonium para tungstate (APT), that is, the surfaces are broken to varying degrees; It is more obvious, that the grain size is larger, and the cracks are less.

(3) Physical and chemical properties

Similarities: both blue tungsten and violet tungsten powders have a large specific surface area, high chemical activity, strong electromagnetic wave (ultraviolet light and near-infrared light) absorption capacity, low bulk density, and strong oxidizing properties. , weak reducibility, good photoelectric effect, and gas sensitivity.

Differences: the measured density of blue tungsten oxide is 7.15g/cm3, and the density measured by X-ray is 7.16g/cm3; the measured density of purple tungsten oxide is 7.7-7.9g/cm3, and the density measured by X-ray is 7.78g/cm3.

(4) Production process

The preparation methods of the two are basically the same, including the hydrogen reduction method of ammonium para tungstate, the closed calcination method of tungsten trioxide, and the direct synthesis method. However, because the ratio of tungsten atoms and oxygen atoms in blue tungsten oxide and purple tungsten oxide is different, the process parameters such as reducing gas concentration and flow rate will be different during production.

(5) Uses

In addition to being used to manufacture tungsten powder, tungstate, and other tungsten compounds, blue tungsten, and violet tungsten powder can also be used as gas-sensing materials, and photodegradation catalysts, invisible materials, functional raw materials for dimming glass, transparent barrier materials. Modifiers for thermal coatings, additives for energy storage battery electrode materials, oxygen scavengers for vacuum equipment, etc.