What Is Tungsten Ring(1/2)

Tungsten steel is a kind of sintered composite cemented carbide material, it’s also known as tungsten titanium alloy, which contains at least one kind of metal carbides. Because of its high wear resistance, heat resistance, corrosion resistance and high hardness, tungsten steel has the very broad range of applications in industry, such as the cutting tool in machining, so tungsten steel can also be called as the teeth of modern industry. In addition, the properties of high hardness, uneasy deformation and discoloration make the tungsten steel be made into all kinds of jewelry, which is very popular. Since tungsten steel’s hardness can reach to 8.9~9.1 Mohs, so compared with the jewelry making process with the other materials, tungsten steel jewelry machining process is more complex and more difficult.
 
Tungsten ring refers to the decorative product that makes with the tungsten steel raw material and will be finished with the cutting, grinding, polishing, etc. up to 30 procedures by using the diamond cutting tools. Because the tungsten steel has white, simple and clear color, and it’s characteristics of uneasy rust, discoloration and no sensitization makes it can also have the excellent performance after being processed of tungsten rings, which have been very popular and been chased by many business people of all ages.
tungsten ring

Tungsten Alloy Astronomical Telescope Counterweight(2/2)

Many astronomers will meet the similar problem: the astronomical telescope has fixed on the support bracket, but the telescope lens would be still shaking in celestial objects observation process. This problem was caused by the insufficient counterweight of the astronomical telescope, and the greater the diameter of the telescope, the shaking will be harder. Ordinary to say, it is indispensable to equip with the equator for celestial objects observation, and it should be fixed on the support bracket before installing it. After installing the equator, and then install the tungsten counterweight.
 
The counterweight for astronomical telescope in general is consisted with the hammer and tungsten alloy connection rod. Using the tungsten alloy connecting rod to penetrate through the heavy hammer which is fixed on the lower end of the equatorial declination axis, then finally installing the astronomical telescope. The hammer’s effect is just like a balance weight or balance counterweight for keeping the balance of the equator and astronomical telescope. So after the installation is ready, we must pay more attention to the counterweight balance between the astronomical telescope and the equator, only the tungsten alloy counterweight is balanced that can guarantee the telescope tens balance in the observation process, thus can reduce the burden of equator. At present, the weight of astronomical telescope counterweight is not made of tungsten alloy material, but tungsten alloy materials’ good characteristics of high density can make it be made into a small volume weight, which also has the equal weight performance, and can reduce the occupied space. Therefore, using tungsten alloy material to make hammer, which can be used in equatorial weight can be expected soon.
astronomical telescope

 

Tungsten Alloy Astronomical Telescope Counterweight(1/2)

In 1609, the Italy astronomer Galileo invented the history of the first astronomical telescope, which opened a prelude to the human to recognize astronomy by using telescope. Astronomical telescope is an essential tool for astronomical research in modern astronomy, it can lead people to detect cosmic, interpret the unknown, and have made great contribution for human civilization. For the general astronomy enthusiasts, if you want to observe the celestial bodies, in addition to the astronomical telescopes, you have to be equipped with equatorial instrument and support bracket. Equator is used to overcome the the influence of earth's rotation when people observing the celestial bodies, and the support is used for keeping the telescope fixed, and preventing the tilt of the astronomical telescope.
 
Generally speaking, whether the astronomical telescope can observe the farther and darker object or not is depending on its own light-collecting ability, the light-collecting ability is more better, the astronomical telescope will see farther and more clear. But such kind of astronomical telescope with well light-collecting ability generally have large caliber, this also means that the balance will become worse during observation process, so as to affect the observed effect. Therefore, it is necessary for the astronomical telescope to add tungsten alloy counterweight. The purpose of adding tungsten alloy counterweight is that the tungsten alloy has excellent wear resistance, corrosion resistance and high density, which can reach the ideal weight requirements with small volume.
astronomical telescope

 

Tungsten Trioxide Electrochromic Mechanism

ElectrochromicElectrochromic material has been able to achieve an electrochromic mainly in the chemical composition of the material band structure and redox properties. For example, electrons are injected and removing by changing the material of the additional electric field of ions, changing light absorption properties of the thin film, setting the thin film to light reflectance, but the detailed mechanism of various electrochromic materials has not been fully identified. Although Tungsten trioxide (WO3) is the first to be discovered photochromic material, but its electrochromic mechanism has been controversial. The experimental data and theoretical analysis models of Deb, Faughnan and Schirmer were established to explain the power of tungsten trioxide electrochromic mechanism.

Deb model
The researchers developed a model that is the first to discover and produce tungsten trioxide thin film electrochromic device, also known as color center model. Deb made of amorphous WO3 study prepared by vacuum evaporation of the rule of law in 1973, the injected electrons are found in cathode form WO3. The oxygen vacancy defects capture F color centers, and ultimately proposed an amorphous WO3 ion crystal structure similar to metal halide (on the alkali halide crystals of the two electrodes voltage is applied and was heated at about 700 ℃. According to neutral and current continuity requirements, positive anion vacancies would cathode electrode near the movement in the positive electrode release halogen. This model explains the colored state WO3 thin film in oxygen to fade after high-temperature heating, the ability to disappear electrochromic phenomenon, the model proposed, but the opinion of Faughnan is that WO3-y film is large amount of oxygen deficiency (y = 0.5), it is difficult to produce large amounts of color centers.

 

Tungsten Trioxide Thin Film Situation

thin flimThin Film material with optical properties, electrical properties, magnetic properties, chemical properties, mechanical properties, thermal properties, thin film with a variety of properties and thus be applied in many fields, for example, as electrical film, optical film, hard film, corrosion film, lubricating film, decorative film, packaging film. Among the film material, tungsten trioxide thin film has a variety of features such as electrochromic, gasochromic, photochromic, thermochromic performance, also has good electrochemical properties, tungsten trioxide thin film has a wide range of applications, such as smart color windows, gas sensors, PH meter. There are researches of tungsten trioxide thin film materials in the sixties, especially in photochromic electricity, electrochemical performance.

More and more scientists began to focus on gas sensing properties of tungsten trioxide thin film. For hydrogen sensitive performance, tungsten trioxide thin film has great potential because when the tungsten trioxide thin film contacts with hydrogen, it can change from colorless to blue thin film. Tungsten trioxide thin film has great potential in gas-sensitive material, tungsten trioxide thin film not only can be used as hydrogen-sensitive materials, also is different from doping elements under different conditions. It is also used for other gases such as NH4, NO2, H2S, O3, O2 and other sensitive material. For example, Au-doped tungsten oxide thin film can improve hydrogen sulfide gas, gas sensitivity; doped palladium or platinum can improve WO3 thin film for hydrogen gas sensitivity.

 

Zirconium Tungsten Electrode

zirconium tungsten electrode

Zirconium tungsten electrodes are kind of rare earth tungsten electrodes which added zirconia (ZrO2) into tungsten-base electrode, produced by powder metallurgy. Its main component are 98 ~98.8% tungsten, 0.91~1.2% zirconia, 0.01~0.07% yttria and 0.01~0.02 cobalt. The tip color of zirconium tungsten electrodes are brown and white. When the doping amount of zirconia is 0.20 to 0.40 percent, the tip color is brown; when doping amount of zirconia is 0.70% to 0.90%, the tip color is white. Zirconium tungsten electrode welding performance lies between tungsten electrodes and thorium tungsten electrode, having good welding performance. In addition, it is mainly produced to improve the shortcoming of tungsten electrode which at high load welding conditions easily melts to contamination the workpiece. Because when zirconium tungsten electrode operates at high load currents, the ends of the electrodes can keep spherical shape thereby reducing tungsten infiltration phenomenon, and it has good corrosion resistance as well, so use a wide range than tungsten electrodes.
 
Zirconium tungsten electrode and pure tungsten electrode generally use in alternating current (AC), and not for direct current (DC), mainly as AC welding of magnesium aluminum and other alloys. At AC welding, zirconium tungsten electrode using ratio is higher than pure tungsten electrode, because during welding the arcing is better than pure tungsten electrodes and arc beam stability. Besides it has good current carrying capacity, good corrosion resistance and weldability. What’s more, it can prevent tungsten infiltration phenomenon and pollution, especially in the high load current conditions the superiority of it is not a substitute for the other electrode. Zirconium tungsten electrodes can also be used for high quality welding rays, mainly because the high quality welding ray has high requirements of tungsten pollution, and zirconium tungsten electrode under high load currents has little tungstenizing phenomenon, so zirconium tungsten electrodes replace tungsten electrode and other rare earth electrode widely use in high quality welding rays fields.

Thorium Tungsten Electrode

Thorium tungsten electrode is kind of rare earth tungsten electrode which adding 1% -2% of thorium oxide in tungsten-based alloys, produced by powder metallurgy. Thorium tungsten electrode is the first used rare earth electrode and has best welding performance. It has low electronic features, high recrystallization temperature, good electrical conductivity, good mechanical cutting and other good properties. However, because thoria is a radioactive material, which is affected by the radiation produced in the welding process and radioactive contamination. The harm caused by radiation on the human body is mainly external irradiation and enters the body through the respiratory and digestive systems occurs in vivo exposure. So people gradually developed a variety of rare earth tungsten electrode to take place tungsten electrodes thorium, such as cerium tungsten electrode, lanthanum tungsten electrodes.
 

Thorium Tungsten Electrode

The tip color of thorium tungsten electrodes is varies according to the amount of doping, when thorium oxide (ThO2) doping amount between 0.90% to 1.20%, the tip color is yellow; doping amount between 1.8% ~ 2.2%, the tip color is red; doping amount between 2.80% - 3.20%, the tip color is purple; doping amount between 3.80% - 4.20%, the color is orange.
 
Thorium tungsten electrodes has good operating performance which can operate well in the current overload, so often as the DC negative electrode or as the positive electrode using in carbon, stainless steel, the nickel alloys, and titanium alloy. The experiment found that the thorium tungsten electrode which content 2% thorium oxide has the lowest work function, so that it can work well in an overload voltage and has long life. Its performance is better than adding 1% thorium tungsten electrode which added 1% thorium oxide. When using the electrode for welding should fast and be careful to take place DC welding in front of the AC welding. Because when AC welding, ball balled will not melt, so the effect is not well as liquid ball.

Tungsten Trioxide Photocatalytic

Photocatalytic also called photocatalyst, it is a kind of light irradiation, it can not afford to change itself, and it can promote chemical reactions, photocatalyst is naturally energy by converted into chemical to act as a catalyst, so that oxygen and water molecules around can excite into highly oxidizing power of the free ions. It can decomposable harmful organic substances and some inorganic substances, not only accelerate the reaction, also cause waste of resources and the formation of additional pollution.

Tungsten TrioxideApplications:
1: Air purification. Tungsten trioxide photocatalyst can use water vapor and oxygen in the air to remove contaminants from the air in the greenhouse, such as nitrogen oxides, sulfur compounds, formaldehyde and other harmful gases. In addition, it can also be used for photocatalytic degradation of industrial waste gas.
2: Anti-fog and self-cleaning. The use of tungsten trioxide to prepare tungsten trioxide thin films has the same photocatalytic action. The respect to the terms of the tungsten trioxide powder has high hydrophilic. Under ultraviolet light strong oxidizing, the power can be generated by the decomposition of organic matter adsorbed on the above-fog and hydrated carbon dioxide that reaches self-cleaning effect.
3: Anti-bacterial. The use of tungsten trioxide photocatalytic photo-generated electrons and photogenerated holes H2O that adsorbed to the catalyst surface is to form an active superoxide ion with strong oxidizing, and bacterial cells or components of biochemical reactions within the bacteria, we can completely kill the bacteria, the degradation by bacteria also release toxic compounds, which prevents secondary pollution caused by endotoxin.

 

Dissolve Tungsten Scraps to Recover Ammonium Paratungstate

Ammonium paratungstate (APT) and tungsten trioxide scraps, as well as substandard products such as tungsten powder and carbide scraps will produce in the smelting process. At present, there are two main ways to deal with these substandard products:
1. Add unqualified products into tungsten products processing as a crystal seed in order to reduce costs and improve the recovery rate of tungsten smelting. Although this process can deal with the substandard products without increasing cost, but it will affect the quality of tungsten powder and carbide;
2. The method that directly dissolve substandard products into alkali to get sodium tungstate solution, and then returned to the production of APT will cost much.

Tungsten scraps

A method that can effectively dissolve APT is proposed in this paper. Mix APT with ammonia, then stir and heat, to effectively get APT reacted with ammonia and generates ammonium tungstate solution.

The specific steps are as follows:
1. Mix APT with ammonia to get the mixture;
2. Make APT dissolved in ammonia, and the tungstate solution;
3. Evaporate and crystallize the tungstate solution to generate APT qualified.

Advantages:
1. recycling tungsten in smelting process at low cost, further improve the recovery rate, reduce energy consumption, and provides a foundation for new technology and product research of tungsten smelting;
2. Shorten the process, increasing the efficiency, and simplify the equipment and operation;
3. Achieve the goal of clean production in tungsten smelting to make tungsten smelting site easier to manage and cleaner.

Purification of Unqualified Ammonium Paratungstate

A method of using unqualified, waste and dirty ammonium paratungstate (APT) as raw materials to generate high purity APT is presented in this paper.

The method includes steps as following:
1. Calcining materials (unqualified, waste and dirty APT) to obtain tungsten trioxide;
2. Dissolving tungsten trioxide generated in ammonia to form ammonium tungstate solution;
3. Filtering ammonium tungstate solution generated, remove the solid impurities, and then evaporate and crystallize to get wet APT;
4. Drying and screening the wet APT crystal to obtain high purity APT with total content of impurities in less than 65ppm.

Characteristic of this method:
1. Using the general and unqualified APT to produce high purity APT is a purification process;
2. High purity APT will meet the follow-up APT deep processing to the production of high quality tungsten products;
3. Through the method of roasting APT to get tungsten trioxide and then dissolved in ammonia can impactful solve the problem of bed effect on apt direct dissolve in ammonia;
4. Part of impurities that difficult to remove is removed in the APT calcination process, and create the conditions for the production of high purity APT products;
5. Solve the practice that low quality of APT back to the main process by alkali dissolution, and improve the recovery rate of production process, reduces cost, and produce high purity APT products at the same time.

 

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