Compared with yellow tungsten or tungsten blue, purple tungsten have: an elongated needle or rod crystal, large surface area, high activity, good ventilation, oxygen index and small series of excellent properties, it is particularly suitable for gas-solid reactions The condition can easily be restored, and the grain is not easy to grow. Therefore, purple tungsten raw material, by lowering the reduction temperature, slow push the boat speed and reduce the amount of equipment and increased boat traffic, such as hydrogen can be produced optimal conditions of quality nano tungsten powders.

Purple tungsten during the restore process, the powder particle size changes all the time, this change mainly from two aspects. On the one hand is a chemical vapor transport growth mechanism. Tungsten oxide and water vapor will generate a volatile hydrated contact tungsten oxide (WO2 (OH2) and the H2 reduction reaction, the reduction product has been deposited on the nucleation of the metal tungsten powder, so that the grain growth; on the other hand is a solid-phase chemical reaction mechanism as the reduction of local time and reducing gas increasing concentration, purple tungsten reacts with hydrogen gas-solid multiphase reduction reaction. On purple tungsten needle or rod-shaped crystals breed countless tiny uniform spherical tungsten oxide grain, purple tungsten with the removal of oxygen atoms gradual lattice rearrangement, and finally gradually transformed into beaded metallic tungsten powder.

Purple tungsten large surface area, high activity, oxygen index is small, permeability, and is most suitable for the preparation of nanoscale tungsten powder materials. Purple tungsten using conventional hydrogen reduction process, reduction by optimizing process parameters, capable of producing high-quality nano-tungsten powder. The preparation process is short, high stability, and no atmospheric emissions of CO2 gases, is an environmentally friendly production methods.
 

Tungsten Powder Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-powder.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten & Molybdenum Information Bank: http://i.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn

Electrospinning technology originated in the 1930s and 1940s. Electrostatic spinning apparatus comprises generally connected to each of the following three parts: a high voltage power supply, a small diameter needle and a capillary tube to collect spinning metal foil, graphite paper collection means.

High voltage power supply for applying a high electric field, so that the charged polymer droplets. Before spinning the polymer droplet collection means reaches solution will evaporate, leaving the crosslinked fibers on spinning collecting device. Needle tube, one end of the high-voltage electrode and the other end connected to the power supply connection collection device containing solution. Droplet surface with a charge of driving under the high pressure will produce the opposite of the surface tension force. With the enhancement of the electric field, the droplets become stretched from the needle by a semi-circular cone, known as the Taylor cone. Taylor cone in the form of droplets ejected from the needle, through the non-stabilized and drawn two processes, thus becomes long and thin, while, as the solvent evaporates, leaving the fibers charged in the After air-curing, arrived on the collection device. Electrospinning the fiber diameter is generally formed about 3nm ~ 1μm.

Electrospinning process can also be applied in the preparation of tungsten oxide. As with WCl6 tungsten source, PVP and DMF were prepared under conditions of 16kV a precursor fibers and prepared at high temperature tungsten oxide nanofibers gas sensing performance as polymer carrier and solvent. With PVB as a carrier by electrostatic spinning process to produce tungsten oxide nanowires have electrochromic properties.

Tungsten Powder Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-powder.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten & Molybdenum Information Bank: http://i.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn

As we all know, the physical characteristics of the tungsten oxide include specific surface area, pore volume, pore size distribution. Ammonium tungsten bronze (ATB), hydrogen tungsten bronze (HTB), purple tungsten oxide (TVO) and blue tungsten oxide (TBO) four kinds of tungsten oxide powder, the use of adsorption / desorption isotherms can be a good measure of the oxide physical characteristics: BET specific surface area such as, micropore volume, the pore volume, pore size distribution and fractional dimension.

(1)TVO has a maximum in the pore volume, the minimum value of the fractal dimension, a very smooth surface, which is conducive to the discharge of water let into the hydrogen, it is beneficial to use a hydrogen reduction process producing ultrafine tungsten powder. However, because the minimum micropore volume, the largest average pore size, pore size distribution and the narrowest having a wedge hole, which is not conducive to the doping process.

(2)HTB has the largest pore volume, maximum value of the fractal dimension (meaning very rough surface), the smallest average pore diameter and have open at one end, closed end cylindrical pore model, this is it for the doping process desirable.

(3)ATB and TBO HTB are smaller than have micropore volume and specific mesopore volume smaller TVO, ATB have a slit-like pore model, TBO having a pore structure open at both ends, for the hydrogen reduction process is, ATB and TVO TBO are not ideal for the doping process it, ATB and HTB TBO are not ideal.

(4)For the hydrogen reduction process or are required to study the physical characteristics of tungsten oxide before the doping process.

Tungsten Powder Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-powder.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten & Molybdenum Information Bank: http://i.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn

Category vapor deposition is very wide, generally refers to a gas phase source material under conditions in which aggregation to the target substrate. Producing a tungsten oxide, typically by physical vapor deposition (PVD). PVD method can be directly used as the source of tungsten oxide, tungsten oxide, sublimation deposition method with high energy evaporation, such as ion bombardment, heating, ion beam, laser radiation and the like. By controlling parameters, can be achieved nano-sized crystals, the formation of morphology, a tungsten source is not necessarily the tungsten oxide, may also be a powder or a filamentous tungsten simple substance, additionally must introduce oxygen or other oxidizing agents to form the WO3 the gas phase. In many cases, PVD method build is WOx instead WO3, color deposits usually can calculate the stoichiometric ratio, usually black film was formed deletion WOx material are formed by means of the oxygen atom; translucent dark blue color film is formed WOx (x = 2.7); yellow-green is a description of the formation of the WOx. Typically, the heat treatment can be controlled by the oxygen content in the resultant crystal phase composition and the stoichiometric ratio. Vapor-phase synthesis commonly used sputtering, vapor evaporation and some other PVD method.

Sputtering target is bombarded with high-energy particles produced atomic film growth method, the advantage is controllable, growing out of the crystal structure of the film has good controllability. A sputtering method is easier to control, can achieve rolling production in mass production, and therefore, in the industrial production of the tungsten oxide, the sputtering method has a very wide range of applications.

Tungsten Powder Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-powder.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten & Molybdenum Information Bank: http://i.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn