Tungsten Oxide

After studies showed a major factors influence blue tungsten oxide (BTO) performance was particle size and production process. The process production conditions including baking temperature, hydrogen flow and baking time. On one hand, under the certain baking temperature, the particle will grow up and the crack will more rough when hydrogen flow decease.  But on the other hand when hydrogen flow increase, the particle will finer and uniform. This is mainly because of increased pressure and permeation of hydrogen will change the internal stress of particle, such stress can lead to lattice distortion, resulting in cracking particles. Therefore, the particles tend to rupture and produce a fine particle powder. Baking time also is an important factor for producing fine blue tungsten oxide. The long baking time, the bigger particle and surface crack of blue tungsten oxide. The experiments show, baking solution temperature at 400 ~ 500 ℃, baking time for 30 to 40 minutes, the hydrogen...

With the development of science and technology, there are more stringent on quality requirements of blue tungsten oxide. The particle size and morphology of blue tungsten oxide are an important factor affecting the performance of it. After studies show that the raw materials and producing process are important factors affecting blue tungsten oxide particle size. Firstly, the raw materials, if it has small particle size then using small raw material to produce blue tungsten oxide the particle of it will finer. Besides the blue tungsten oxide particle will more uniform.Secondly is producing process. The main factors which influence particle size is baking temperature, hydrogen flow and baking time and so on. Effect of baking temperature is at the beginning the crack will increase with the baking temperature increase, besides the rule crystal turn to irregularity small particle. But when the reaction reach to a certain degree the blue tungsten oxide particle crack will decrease with the...

Fine tungsten powder is an important raw material for producing tungsten carbide powder, to improve the performance of carbide tungsten is necessary to reduce or eliminate the coarse tungsten powder particles. Otherwise it will cause tungsten carbide cracks, fracture and other phenomena in the course. After studies the process of using blue tungsten oxide as raw material to produce fine tungsten powder research found that by using exceptionally pure ammonium paratungstate calcinate in ammonia to get blue tungsten and then go through the cyclic oxidation producing fine tungsten powder, and the tungsten powder properties is better which is less coarse. Producing process as follows: 1. Slow heating exceptionally pure ammonium paratungstate which is in ammonia to 600 ℃, when the temperature reach 600℃for 10min heat preservation to produce  blue tungsten oxide. 2. To obtain tungsten powder by restoring blue tungsten oxide in hydrogen. 3. The obtained tungsten powder slowly heating ...

Oxygen index have certain impact on the performance and morphology of blue tungsten oxide, researcher determination of oxygen index of blue tungsten oxide by weight method. After experimental data analysis found that the baking temperature has great impact on oxygen content and the color of blue tungsten oxide. When baking temperature at 350 ~ 500 ℃, the oxygen index between 2.96-2.90. Changing the baking temperature, the color and oxygen content of blue tungsten oxide also will change and surface gloss index has varying degrees of change. At 350 ℃, blue tungsten oxide ’s color is yellow-blue and has high oxygen index, matte. As the temperature increases, blue tungsten oxide gradually be reduced, when the baking temperature reaches at 450 ℃blue tungsten oxide’s color translated into blue-black and surface of it has metal light, oxygen index of 2.94. When baking temperature reached 500 ℃, oxygen index of 2.90, blue tungsten oxide color is blue-black. As the temperature continues to ri...

Fine and uniformity tungsten powder are key point for producing carbide, and micron and submicron tungsten carbide powder is useful to producing carbide. According to the relevant academic report found that single tungsten oxide can produce submicron or micron tungsten powder. Using violet tungsten oxide (VTO) producing fine tungsten oxide not only the process of it is simple as well as process parameters are easy to control and also equipment are not complex etc. Producing process as follows: 1. VTO were first reduction in hydrogen, along a first temperature of 640 ℃, the second temperature of 760 ℃, third temperature of 860 ℃, when the temperature reaches 860 ℃ heat preservation for 20min. 2. in the air at 500 ℃ making tungsten powder to oxidation with slowly heated for the first time, then heat preservation for 10min. 3. Replace the first step and second to continuous cycle reduction reaction. 4. Using alcohol on the analytical results above steps were dispersed pattern, then ...

Tungsten oxide has good physical and chemical properties, so it can be widely applied in many different fields. Its ultra-fine powder has a strong absorptive capacity of the electromagnetic wave, so it can apply in solar energy field which can be an absorbing material, and in the military field it is an important stealth material. And tungsten oxide has a special catalytic properties in the fuel cell can be used as the anode electrode catalytic materials, as well as can be low-temperature superconducting materials, but also often doped with TiO 2  as a photocatalyst and so on. Tungsten oxide film based on tungsten oxide powder material having a broader application, it can transform it presents color when giving appropriate optical radiation or using electric field. And this is photochromic or electrochromic. And at present these technologies are widely used in electrochromic windows, large information displays, and automotive mirrors and so on. Meanwhile tungsten oxide for NO X , ...

Purple tungsten oxide using the APT as raw materials,which is during at the closed furnace in the industry. Under certain conditions, adding NH3 during calcination, and the NH3 will decompose H2 and N2, it will form a wet hydrogen atmosphere furnace in the stove, so that APT under mild reducing atmosphere, gradually decompose, generating purple oxide reduction. There are many factors in the process of preparing purple tungsten, one by the hydrogen reduction of tungsten oxide mechanisms apparent hydrogen greater humidity, the temperature required to obtain the higher tungsten purple, so choose the calcination temperature should be 770 ~ 815 ℃, Second, in the calcination process feed speed, tube speed, NH3 traffic and others factors affect the production of tungsten purple in varying degrees. In the preparation of tungsten purple we should to coordinate various relationships in order to produce a single phase purple tungsten. Its chemical equations are: 3 [5 (NH4) 2O · 12WO3 · 5H2O] = ...