Purple tungsten oxide (Violet Tungsten Oxide, VTO), referred to as purple tungsten. Purple tungsten oxide refers to paratungstate (Ammonium Paratungstate, APT) as raw materials under certain conditions Calcination, decomposition, reduction generated purple tungsten oxide. General purple or blue-purple crystalline powder. By strong fissile octahedral structure, intrinsic crystalline needle and rod. Purple Tungsten is a tungsten oxide, the chemical formula for WO2.72 or W18O49. Purple and yellow tungsten oxide, tungsten (the yellow tungsten WO3), blue tungsten oxide (referred to as blue tungsten W20O58 or WO2.90) and brown tungsten oxide (WO2) collectively known as tungsten oxide. The tungsten oxide can be used as raw material for the production of tungsten powder, tungsten because of its unique nature purple to purple tungsten tungsten powder products as raw materials, has generated fast, fine-grained and so on.

Ultrafine cemented carbide demonstrates a superior combination of higher wear resistance and higher hardness. The key factor to obtain ultra- fine carbides with pure, fine and homogeneous grain is using finer starting tungsten carbide powder with tight particle size distribution. Two kinds of ultra- fine carbides were synthesized by adopting blue and purple tungsten oxides as rawmaterials respectively. And, after contrasting the properties of the two kinds of alloy,it was concluded that the alloy using purple tungsten oxide as raw material has better over- all properties with smaller grain size, higher strength and hardness.

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Ethanol and distilled water as a dispersing agent, silicon and silicon acid mesoporous materials than 3:1, the calcined at 600℃ and after HF treatment of tungsten oxide N2 adsorption - desorption, N2 adsorption - desorption isotherms at relatively pressure (p / p0) is between 0.1 to 0.2 of a sudden the weak, the relative pressure of about 0.6-0.8 adsorption curve there is a clear conflict more, and there is between the branch and the adsorption and desorption branches noticeable lag ring, which is produced by the N2 in the pores of capillary condensation phenomenon, which also indicates that the material prepared mesoporous channels.

Preparation of mesoporous material having pore diameter of two-channel. Reasons for the formation may be due to the dual aperture silicotungstic acid SiO2 pore filling during the filling of dissatisfaction, or in the process of formation of the tungsten oxide polymerization between molecules caused some vacancies in the bore, so when removing the SiO2 pores becomes large so that, while forming a double-aperture is ethanol and distilled water as the dispersant, silicotungstic acid material than the silicon mesopores 3/1 when calcined at 600 ℃ tungsten oxide mesoporous material prepared The structural parameters, the specific surface area can be seen that the dispersant is prepared using ethanol as tungsten oxide mesoporous material with a pore volume of distilled water are higher than the dispersant.

Ethanol at room temperature The contact angle of the mesoporous silica surface was 11°, the water contact angle of the surface of the mesoporous silica is 26 °, than ethanol distilled water described mesoporous silica having better wetting properties, more conducive to the silicon acid into the pores of the silica and the formation of mesoporous materials.

Mesoporous silica as a hard template, and silicon acid compound, and then the HF treatment to remove silica prepared by having a large specific surface area and pore size of mesoporous tungsten oxide dual optimum conditions are: Silicotungstic acid and mesoporous silica composite material ratio (m (WO3) / m (SiO2)) in between 3 to 4:1, and calcined at 600-750 ℃. When using ethanol as a dispersant compound , the resulting mesoporous WO3 specific surface area and pore volume than when distilled water as the dispersant large, mainly due to ethanol ratio of distilled water to the mesoporous silica having better wetting properties.

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Composites calcined in the silica pores of silica acid is converted to form the influential tungsten oxide, tungsten oxide calcination temperature of crystallization and its mesoporous structure. This paper explores at 550-950 ℃ between different calcination temperature impact of mesoporous tungsten oxide structure. Ethanol as a dispersant, and silicotungstic acid silica mesoporous material than m (WO3) / m (SiO2) 3/1, after calcination at different temperatures HF treated tungsten oxide. When the calcination temperature at 550 ℃, almost no diffraction peaks in the small, indicating the degree of structural ordering poor, while N2 adsorption - desorption characterization of the specific surface area of ​​42.7m2 • g-1, and after more than 600 ℃ calcined surface area of ​​68.0m2 • g-1 there were significant decreases when the calcination temperature is 600-750 ℃ ​​when, in the vicinity of 2θ = 1 ° there is a clear diffraction peaks, indicating that the tungsten oxide upon calcination crystalline SiO2 is preferably within the hard model , ordered mesoporous structure after HF treatment of tungsten oxide is preferably, but in a small angle diffraction, no diffraction peaks were observed secondary peaks, indicating that the mesoporous structure is not a good long-range order in the calcination temperature reached 850 and 950 ℃, the structure of the degree of order is poor, there may be caused by high temperature volatile part of the tungsten oxide, thus affecting its structure degree of order.

Small angle XRD patterns of ethanol as a dispersing agent in a different material than silicon tungsten acid mesoporous silicon when, 600 ℃ calcination and get treated by HF tungsten oxide mesoporous materials can be seen when the silicon and silicon-mediated acid hole material ratio m (WO3) / m (SiO2) is 2:1, the figure in the small-angle XRD diffraction peaks, showing that structural order is poor, while the N2 adsorption - desorption characterization of the specific surface area of ​​40.7m2 • g-1, and calcined at 600 ℃ than the surface area of ​​68.0m2 • g-1 significantly decreased compared to when the material ratio 3/1 and 4:1, there is a distinct diffraction peaks near the (211), Description In this mass ratio is preferably within a range of structures can be prepared tungsten oxide mesoporous material. When silicotungstic acid and mesoporous silicon material ratio 5:1 when, in the small-angle XRD pattern of the diffraction peaks is not obvious, indicating that its structure Sequence poor, probably due to the content of tungsten is too high, the silicon oxide outside the tunnel crystallization.

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Electrochromic film materials include various organic and inorganic compounds, of which the most studied is tungsten oxide, the main methods of preparation include vacuum thermal evaporation, electron beam evaporation, sputtering, vapor deposition, electrodeposition and sol - gel method. Electrochromic film a certain temperature heat treatment can improve their adhesion and cycle life, but the high temperature heat treatment tends to affect the magnitude of the response time and color film. General physical preparation methods require high temperature heat treatment, such as electron beam evaporation method needs a heat treatment 500e, 350e thermal evaporation requiredRF sputtering need 200 ~ 300e. These methods are often due to expensive equipment, technical complexity and demanding process conditions and subject to certain restrictions; the chemical preparation of the sol - gel method is a simple equipment, low temperature deposition uniformity and easy preparation method for preparing a large area, but usually 100e need more heat. Alkoxide method as required 250e of heat treatment, ion exchange need 150e, halogenated oxidation need 120e. Bessiàre etc.

80e heat treatment method has been reported, and in a soft deformable polyethylene terephthalate (PET) Preparation of the electrochromic thin film on the substrate so as to cover any irregularities in the surface shape of the object, but the film thus prepared The cycle life of only dozens of times, can not meet the actual needs. Sodium tungstate as raw material, ion exchange acid solution, ethanol, and polyvinyl alcohol (PVA) as an additive, by sol - gel prepared by the superior performance of the tungsten oxide electrochromic films. This film just 75e of the heat treatment temperature, the driving voltage of -1 ~ + 1V, fully colored and fade time of only a few seconds, coloring in aqueous solution - fading cycles up to 600 times, the color can be kept after coloring number of days.

The resulting film is colorless and transparent, colored blue after uniform color. At 300 ~ 900nm wavelength, variation in the film of the colored state and the faded state transmittance. When fading state, the transmittance in the visible and near-infrared region are more than 93%, but in the near-ultraviolet region due to the absorption of the matrix glass, so that a decrease in transmittance. When the colored state, in the region of 600nm or more has a good absorption, transmittance of 21% or less, which is displayed with its appearance coincides blue. Transmittance in the colored state of 600nm or less significantly increased, but the colored state and the faded state at 500nm transmittance difference also more than 50%. Test results show that the film color changed significantly, having good light controllability.

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1992 Kresge first reported mesoporous silica materials with regular pore structure of MCM-41 called for the study of the molecular sieve material has opened up a new field. Because of mesoporous materials with large specific surface area , uniform adjustable aperture (2-50nm), rules controllable appearance, high thermal stability and hydrolysis resistance and other properties, so that in the separation, adsorption, catalysis, biological materials, information materials, carbon nanotubes prepared applications in areas such as more and more people's attention.

Preparation and properties of mesoporous silica mesoporous silica material has been widely studied, with different structural features have been very easy to prepare, but its performance is difficult to meet the application requirements of different areas, so a non-silicon-type mesoporous research materials more and more. Because the characteristics of tungsten oxide itself in the field of catalysis applications, electrochromic electrode materials, energy storage and microwave materials, so that the mesoporous tungsten oxide material is expected to play a more effective role in these areas. About Preparation of tungsten oxide mesoporous materials at home and abroad have been a number of related stories. The preparation method can be divided into two categories, one is a long-chain organic compounds as a template, tungsten hexachloride tungsten source, after the ethanol gelation by calcination or solvent extraction to remove the organic template agent to prepare tungsten oxide mesoporous materials, but mesoporous tungsten oxide high-temperature calcination easily collapse, and the use of extraction to remove the organic template, and it is difficult to be repeated extraction divisible, while tungsten oxide difficult fully crystallized, so these methods ultimately difficult to get a better structure of tungsten oxide mesoporous materials; the other is hard template method, which uses mesoporous silica as a template to make mesoporous tungsten oxide after its crystallization temperature HF to remove the template, the template is removed such methods in milder conditions, and the template is removed completely. Most of phosphotungstic acid as tungsten source, thus the introduction of impurities of phosphorus, and the emphasis on the application performance of mesoporous tungsten oxide research, unexplored The preparation conditions for the tungsten silicon acid source mesoporous silica (KIT-6) as a template, the template was prepared to explore with a hard tungsten oxide mesoporous materials and preparation conditions.

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From the beginning of the industrial revolution, human society has made tremendous progress, while paying the environmental pollution and ecological deterioration of the enormous cost, from photochemical smog to acid rain, air pollution is getting worse, NO2 in which plays a very important addition to the impact .NO2 volcanic eruptions and other natural sources of foreign, mainly from the burning city car exhaust fuel. In addition, industrial production process can produce some NO2. It is estimated that, worldwide anthropogenic pollution emission of nitrogen oxides per year is approximately 53Mt. The main harm the atmosphere, water and soil, etc., can cause direct harm to the human respiratory system and eyes. Our indoor air quality standards in the ceiling on the NO2 concentration of about 0.12ppm.

As people gradually improve the quality of life requirements, detection of NO2 gas in recent years has become an important topic, and then study the gas sensor has achieved rapid development, wherein the metal oxide semiconductor material meteoric rise, SnO2, ZnO, WO3, etc. are been extensively studied, but previous studies showed that the outstanding problems of these materials is that the higher operating temperature, selectivity and sensitivity, such as less than ideal, is not conducive to the development trend of integration and low power consumption, so people using the included material doped composite, low-dimensional technology, using different preparation methods, research and even low ambient temperature sensitive materials and other ways to reduce the operating temperature of the sensor.

Porous silicon because of its unique optical properties at room temperature and gas sensing properties of the application in the biomedical field, since the 1990s, are more and more attention. Porous silicon surface area because of its great and has a high surface activity, the external environment can absorb large amounts of gas molecules change their electrical properties or optical properties exhibited gas sensing performance. Application of porous silicon as a gas sensing material, generally use optical excitation, doped with another material or composite approach to achieve the purpose of improving the sensitivity or selectivity. Tungsten oxide as a common n-type metal oxide semiconductor material, also has good electrochromic properties and excellent gas sensing characteristics. In the n-type ordered porous silicon surface layer of tungsten oxide thin films by magnetron sputtering using porous silicon at room temperature and gas sensing performance of tungsten oxide NO2 better sensitivity advantages of gas sensing properties of composite structures. Aperture ordered porous silicon is between mesoporous silicon and macroporous silicon. Sufficiently large pore size and high porosity conducive to the formation of a good film with tungsten oxide composite interface, but also ensures high sensitivity to gases.

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Aggressive jigging

Tungsten’s turbo sink-rate isn’t just about bypassing unproductive water to get to active fish. Its fast fall also triggers bites.

“You can really move tungsten around and create heavy jigging strokes,” Brosdahl said. “A slow, natural fall is nice when you’ve got a cold front or are dealing with really finicky fish, but when fish are aggressive a fast fall triggers them. And, you’ve always got the option to play cat-and-mouse with a crappie by slowly pulling the jig away from them.”

Fast jigging strokes become increasingly critical at night. After crappie lose interest in glow-painted baits, Brosdahl finds vibration becomes the dominant fish attractant in the dark. Compared to lead, a tungsten jig can be pounded and twitched more aggressively to create heavy vibrations and call-in crappie by “talking to their lateral line.”




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Straight, fast drop

Compared to a lead jig of equal size, a tungsten one is heavier and sinks faster. This has advantages in many crappie scenarios.

Cover water - Tungsten’s fast drop allows anglers to rapidly fish a hole. This makes prospecting more efficient, especially in deep water. Consider how it’s easier to cover water in a boat using a lure you can cast a country mile versus one with a limited range. On ice, every hole represents a cast. Fast-sinking tungsten makes quick work of covering the water column, bypassing unproductive sections, and determining if fish are around.

Get back to biters - A high-speed drop lets anglers capitalize on brief, feeding windows. The faster the bait returns to the strike zone, the more crappie one can catch during short-lived bites.
Straight down - In addition to sinking fast, a round tungsten jig drops straight down. This makes it well suited when a precise drop is needed to avoid snags around timber, vegetation, and rock cribs.
Making clouds - A heavy tungsten jig is a great tool for banging bottom to attract fish. Make impact with the floor, snap the jig up, and let it smack the silt again. Do this a few times to stir up the bottom and create silt clouds. The sediment plume attracts crappie.

At times, Brosdahl uses a heavy spoon to make massive silt clouds, then reels up and switches to a small jig. Tungsten makes this 1-2 punch fast and efficient.

Density desirables - A tungsten jig emits ticking sounds when hit on hard bottom.

Brosdahl uses this tactic more for crayfish-eating jumbo perch, but finds banging tungsten can attract crappie when fishing hard-bottom areas or isolated rock piles.

Accelerated fall - Tungsten sinks well on a spinning outfit. No complaints here. But, these days Brosdahl often uses a straight-line reel, like the Frabill 371, for more speed.

The 371’s ultra-smooth, free spool quickly feeds-out 3-pound fluorocarbon, helping tungsten jigs reach terminal velocity on the drop. The fact straight-line reels eliminate line twist is a bonus when it’s time to finesse a slab to hit.




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Tungsten ice jigs are a hot trend on hard-water. Lure selections from manufacturers are growing, and more anglers are seeing the unique advantages tungsten provides on ice.

Small jigs that “fish heavy” are a main ingredient for many crappie ice fishing tactics. Since tungsten is much denser and approximately 30-percent heavier than lead, it gives new options for jig-size and weight combinations. This has benefits when downsizing, for instance. Tungsten also sinks faster than a similarly sized lead jig, which is an asset in deep water.

Ice-fishing guru and full-time guide, Brian “Bro” Brosdahl of Max, Minn., is well versed in the virtues of tungsten jigs for crappie. Here are 4 reasons tungsten jigs are standard in his ice fishing box:

Punch slush
Fast drop
Aggressive jigging
Great for downsizing

Punch slush
“Tungsten punches through a slushy hole nicely without needing to go to a gaudy-sized lead jig,” Brosdahl said. “This reason alone is why I use tungsten so often.”

To appreciate this statement, we must take a page from Brosdahl’s stealth fishing handbook. To Bro, slush is your friend. While most anglers scoop it out, he kicks extra slush into a freshly drilled hole. The reason: a slushy hole reduces light penetration for a more natural setting below. In contrast, a clean, slush-free hole allows a spotlight-like beam to shine in water, which can spook clear-water crappie.

The challenge is getting a small bait through the thick, icy soup. For tiny lead jigs, Brosdahl often uses a method he calls jousting. With the jig at the rod tip, he thrusts the rod into the slush to get the tiny jig below the debris before opening the bail and letting the bait sink. He’s never broke a rod, but he’s seen others snap sticks trying the method.

With tungsten, jousting is rarely needed. Average-sized tungsten jigs easily punch through slush. When the slush is extra thick, or when using a tiny tungsten jig, Bro makes a pilot hole in the slush with his Humminbird transducer.

Brosdahl admits he sometimes needs to reach in and pull a big crappie through the slush to land it. But, it’s a small hurdle and a better option than not hooking them at all.




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Tungsten as a strategic non-ferrous metals, because nature has a high melting point, high elastic modulus, high hardness, good thermal conductivity and excellent fracture toughness, they are applied to cemented carbide, high-density tungsten alloy, tungsten wire, tungsten and many other fields. With the development of modern industrial technology, the traditional tungsten powders made of tungsten products has been difficult to meet industry needs. And a large part of the quality factor depends on the performance of tungsten products tungsten powder raw material, and therefore its need to prepare good performance tungsten products, must be prepared by the excellent quality of tungsten powder.

You can make use of X-ray diffraction, scanning electron microscopy and surface area analyzer to study the process of W powder phase structure, evolution and mechanism of powder morphology and particle size reduction of WO3. WO3 during the restore sequence into WO2.9, WO2.72, WO2, eventually reduced to W. W in WO3 powders hydrogen reduction process, smoothing rule WO3 has hexahedral rough topography becomes a hexahedral, and with the reduction process, the larger secondary particles into smaller particles. In the hydrogen reduction of WO3 and WO2.72 WO2.90 process, the powder specific surface area is increasing, decreasing powder size, but reduced to the WO2.72 and WO2 WO2 reduced to W in the process, the powder specific surface decreases, increasing the particle size of the powder.

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