Tungsten oxide is a kind of tungstic anhydride, which is a tungstate product. Tungsten oxide type includes tungsten trioxide and tungsten dioxide. In actual industrial production, it is rare to have tungsten dioxide.
Tungsten dioxide is also known as brown tungsten oxide. The formula WO2 tungsten dioxide is an intermediate transition state of ammonium paratungstate into tungsten trioxide. Its appearance is tan monoclinic powder crystal, and tungsten dioxide is the most commonly known, the role is to manufacture tungsten powder and tungsten trioxide.
Tungsten trioxide, also known as yellow tungsten oxide, chemical formula WO3, is the main tungsten oxide product of our country before the eighties. Yellow powder is insoluble in water, soluble in alkali and slightly soluble in acid. Its density is 7.16 g / cm3; The melting point is 1473 ° C; the boiling point is about 1700 ° C. Mainly used in the system of high melting point alloys and cemented carbide, tungsten wire and fire gas sensitive materials, but also for photocatalyst materials.
Blue tungsten oxide is also known as blue tungsten, chemical type W2.90. After the reform and opening up in 80s, China began to produce the blue powder in accordance with the requirements of international orders. Blue tungsten has a certain crystalline form, which is larger than the surface and is easy to be doped. The tungsten carbide powder and tungsten powder are better than those with yellow tungsten. Therefore, after 80s, blue tungsten has gradually replaced the mainstream of the yellow tungsten oxide in the market, and is the main product of the tungsten oxide market.
Violet tungsten oxide, also known as purple tungsten, chemical formula 2.72, which in broad terms can be considered a branch of blue tungsten, the appearance is purple or purple red fine crystal powder. Compared with blue tungsten and tungsten, violet tungsten has a special surface and the highest chemical activity. Therefore, ultraviolet tungsten is the most suitable for the production of ultrafine tungsten powder. At the time of increasing the requirements for the performance of cemented carbide, the demand for nanometer tungsten powder is also contending. Therefore, the market of violet tungsten is becoming bigger and bigger.
At present, the tungsten oxide products that are mainly traded on the market are four kinds. Tungsten oxide can only be the final product of tungsten raw material in the whole process of tungsten application, and it is also the main product of China's exports at present.