In 1985,Mikiya Toshio and Shoji Michihiro invented the first tungsten carbide tipped annular cutter.It had been designed as a cutting tool, made from tungsten carbide material on its tip, with multiple cutting edges and hollow body ,combined extreme hardness and durability with a wide range of possible applications in holes making for both ferrous and non-ferrous metals.



Since at the periphery of the hole, the tungsten carbide tipped annular cutter cuts only has an annular groove and leaves a solid core or slug at the hole center, it is an ideal option for lower speed,higher price and less efficient twist drills and hole saws. The function of Annular Cutters is more or less same as a hole saw but differs in geometry and material. Annular cutters are faster, easier and are more accurate than the conventional twist drills or drill bits.

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Using sol-tungsten method produce trioxide film the technology is very mature, and this method also provides the possibility for large-scale preparation of tungsten trioxide films. With further study of this method, at present some researchers using tungsten powder and molybdenum powder as raw material with hydrogen peroxide and acetic acid effect produce original solution of tungsten oxide and molybdenum oxide. These solutions can place for many days without the risk of precipitation. Using X-ray diffraction (XRD) and scanning electron microscopy (SEM) to study the film structures and surface morphology, it found that the obtained film has agood electrochromic properties. Prepared process as follows:
(1) Preparing 10g of tungsten powder and molybdenum powder react with 100ml hydrogen peroxide solution (H2O2 content of 30%) to produce tungsten oxide and molybdenum oxide solution.
(2) preparing ice water so the reaction temperature at 0 ~ 10 ℃.
(3) After precipitation and filtration to give a clear solution, was added 100ml of glacial acetic acid, at 55 ℃ was stirred at reflux for 24 hours.
(4) putting acidified solution at 60 ℃ oven drying, and take some desiccate dissolved in the solution by 1: 3 weight ratio to obtain original solution of tungsten oxide and molybdenum oxide.
(5) with an ultrasonic cleaning ITO substrate soaked in the same amount of tungsten oxide and molybdenum oxide, a while after slowly pull it out and placed in an oven heated to 100 ℃ for 1 hour.
(6) After natural cooling obtaining a film of tungsten and molybdenum oxide.

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Tungsten oxide electrochromic films are widely used in modern society, and therefore improve the application of tungsten trioxide for widely plays an important role. And to improve the tungsten trioxide electrochromic the key point is to short the ions diffusion and transport time in the material. In addition to using the sol-gel method and magnetron sputtering method, with further research there are many methods for produce tungsten trioxide eletrochromic which has greatly improved. Such as using hot filament chemical vapor deposition method produce electrochromic films. Nano crystalline of tungsten trioxide films annealed at 300 ℃ air, the film primarily monoclinic crystal. Crystalline tungsten trioxide compared with conventional amorphous then performance are more stable in a sulfuric acid solution H + cycle and the usage rate can up to 3000 times. And nano tungsten trioxide films have a greater surface area, so the coloring of it will better than conventional amorphous oxide film. And using hydrothermal synthesis method can produce controlled morphology of tungsten trioxide nano particles, and then based on this using drop-casting method to produce tungsten trioxide films. Tungsten trioxide film in the lithium ion electrolyte compare with sulfuric acid solution the H+ will smaller than Li, higher power density, faster response times and greater coloration efficiency.

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Tungsten trioxide electrochromic response time is based on the ion/electron diffusion and transport speed on the internal material. Due to the size of the ion is much larger than electrons, thus transportation and diffusion of ions is the slowest part during the whole reaction process. Therefore, to improve the tungsten oxide electrochromic response time is the key to shorten the ion diffusion and transport time in the material. Limit ion injection / withdrawal rate has two main factors: First, the ion diffusion coefficient. Second are the ion diffusion pathways. With further research, at present, to enhance rapid response time of WO3 films, mainly change the microstructure of WO3 film. For example, using sol - gel method to produce WO3 • H2O, because the (WO4) 2- surrounded by water molecules so it will cause reactive ion (H +, Li +) are more likely to spread, thus greatly reducing the reaction time. According to double injection / extraction mode, thereby increasing the surface area of ​​the film can be improved electrochromic properties. And using magnetron sputtering method to produce ZnO thin films which is a base material produce where it is on the ITO conductive glass. And then produce ZnO nano rods. Finally using pulsed laser deposition method let WO3 particles deposited on the surface of the nanorods. Tests show that the stability of tungsten oxide film and the corresponding rate has been greatly improved.

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In inorganic electrochromic material there are most of the transition metal oxide and its derivatives. In inorganic electrochromic material which can be divided into different type which is according to the different coloring process such as reduction status coloring staining material, oxidation status staining material and oxidation/reduction status all staining. Tungsten trioxide is reduction status staining material. At present, there are many inorganic electrochromic material, such as tungsten trioxide (WO₃), nickel oxide (NiO_x) and Prussian blue (PB). And WO₃ is the most studied and the most mature one electrochromic material. WO₃ is perovskite structure which is made of WO₆ octahedron. W atoms occupy the cube apex. O atoms occupy the position of each cube. When the center position vacant the valence states of W is +6, then WO₃ films are transparent. When the cation fills the center position, oxidation status of W will reduce to form a mixed valence compound W^V and W^VI, and WO₃ film is blue. Although the mechanism of color changing of film is not clear yet, but double injection model was accepted by most scholars. That mean the color of tungsten trioxide films change is due to hydrogen ions and electrons injected simultaneously to film material. WO₃ electrochromic reaction can be represented by the following chemical equation: WO3 + xe^- + xH ⁺ ← → HxWO₃.

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At the early time, after studied electrochromism of tungsten trioxide researchers found that the films color change due to the hydrogen ions and electrons are simultaneously injected to it.  Besides the chemical reaction process is reversible. However, It also led many scholars believe that tungsten trioxide gasochromic also cause by the hydrogen ions and electrons injected. But after study found that double-injection model of gaschromic is more complicate than electrochromic’s. In the double injection model of gasochromic, the coloring process is by dissociate H2 into H atoms or H ⁺ which is absorbed to catalytic Pt particle surface, H atom transfer from the metal particle surface to the surface of the tungsten trioxide film, and then injected into the tungsten trioxide film. Then make the color of the film change. The bleaching process also adsorbed O₂ which is on the catalyst surface, then transfer to WO₃ film surface, forming a strong chemical activity of O atom or O^2-, so that it can attract out H ⁺ which is exist in film, and with H ⁺ to form H₂O molecules. Therefore H₂O released from the film causing discoloration of the film. From this we can see that fade and coloring is an irreversible chemical reaction process.

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Tungsten stream mouth, also called iridium stream mouth, which is made of an alloy of tungsten and iridium, which has the following properties: wear-resistant, high temperature resistance, corrosion resistance, erosion resistance, high specific density, high hardness, high melting point, good thermal conductivity, good conductivity, low expansion characteristics at high temperatures and dimensional stability, good chemical stability and other properties.

Tungsten stream mouth can be used as funnel-type fittings to quantitatively discharge high temperature dissolved pulp outwardly, that is to say, it could be used as a key part for the production of refractory fibers. The following is something about silicate aluminum refractory fiber. Because overheating melt (silica and alumina) will discharge through the mouth and spray into the fiber, and overheating melt temperature is about 2300 ℃, therefore you need to use tungsten iridium stream mouth. With the continuous expansion of aluminosilicate refractory fiber manufacturing industry, the market demand of tungsten iridium stream mouth is also rising.

 

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Tungsten stream mouth, also called iridium stream mouth, which is made of an alloy of tungsten and iridium, and takes advantage over the two elements. Tungsten owns the following properties: high specific density, high hardness, good thermal conductivity, good conductivity, heat resistance, wear resistance, corrosion resistance, low expansion characteristics at high temperatures and dimensional stability. In all metals, tungsten has the highest melting point (up to 3380 ℃), maximum tensile strength (at the temperature of 1650 ° C) and the lowest vapor pressure.

Iridium owns high temperature corrosion resistance, high melting point, good chemical stability and other properties. In tungsten iridium alloy, tungsten and iridium performance has been very good fusion of two elements, such that product hardness, strength, abrasion resistance, and heat resistance have been further improved, and then the consistency of the product can be better ensured. Tungsten iridium stream mouth has become the indispensable equipment component of high-tech crystal glass industry.

 

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Tungsten iridium stream mouth is composed of tungsten substrate and iridium tube, which takes advantage over the two elements.

If the density of tungsten substrate is higher, the high temperature resistance and corrosion resistance of product will be the better.  According to the production and use of statistical analysis, the provisions of tungsten substrate density should not be less than 17.7 g / cm3.

The bonding strength between tungsten substrate and iridium tube is an important indicator of product life. If the bonding strength is better, the high temperature resistance of product will also be better and product will serve a longer life. According to feedback results and the current state of the art technology, the provisions of tungsten substrate and iridium tube bonding strength will be judged qualification when the product is applied 1000 g weight for 10 seconds and would not off.

Iridium stream mouth tungsten surface should be smooth, no glitches, cracks, folds, peeling, holes and other defects, to ensure its service life.

 

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Tungsten iridium stream mouth is composed of tungsten substrate and iridium tube, which takes advantage over the two elements.

Tungsten properties: high specific density, high hardness, good thermal conductivity, good conductivity, heat resistance, wear resistance, corrosion resistance, low expansion characteristics at high temperatures and dimensional stability. In all metals, tungsten has the highest melting point (up to 3380 ℃), maximum tensile strength (at the temperature of 1650 ° C) and the lowest vapor pressure.

Iridium properties: high temperature corrosion resistance, high melting point, good chemical stability properties.

Tungsten and iridium properties have been very good fusion of two elements, such that product hardness, strength, abrasion resistance, and heat resistance can be further improved.

Tungsten iridium stream mouth was prepared by powder metallurgy method with hydrogen sintering and other process. It is mainly used as high temperature resistance container in the heating generator of induction furnace, rare earth metal smelting, and the quartz glass smelting for high temperature, and it can also be used as a funnel-type fittings to quantitatively discharge high temperature dissolved pulp outwardly. In the glass and ceramics industry, tungsten stream mouth is a very critical part in ceramics production.

 

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