Tungsten copper contacts materials, also known as tungsten copper electrical contacts materials, which is used to control the current of the switch- on and off, mainly used in contact switch, magnetic motors, relays, circuit breakers and other components. Contacts performance will directly affect the operation of the entire electrical system function, especially modern automatic control systems, communication systems and other large power system, because there are many contacts in them, if one or several of whose performance will derogate, it will make this system work in a mess, can not even run, therefore, the performance of tungsten copper contacts work performance should be improved.

Performance requirements of tungsten copper contacts are shown as follows:
1. In order to reduce heat loss when current flows through the contacts and reduce the tungsten oxide of contacts surface , tungsten copper contacts are required to have high electrical conductivity, thermal conductivity;
2. Under the arc or spark action, in order to reduce contact wear and the likelihood of the occurrence of welding of the contacts, tungsten copper contacts required to have a high melting temperature, high boiling point, high melting and evaporation heat and high heat;
3. Stable chemical performance, and its requirements of being polluted by the environment is that the change of contact resistance is small; the contact resistance is stable;
4. Appropriate elasticity and hardness, if the hardness is too large, the contact area is small, and if flexibility is greater when the contact is closed, the wear due to bounce between the contacts will increase;
5. It has an easy machining, welding performance;
6. Lower prices.

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The natural mineral formations containing tungsten in amounts that make their extraction economically feasible. The chief minerals of tungsten are wolframite,containing 74-76 percent WO₃, and scheelite, containing 80 per-cent WO₃. The minimum concentrations of tungsten trioxide at which it is profitable towork tungsten ores at the present level of economic and technological development (1960-70) are of the order of 0.14—0.15 percent for large deposits and 0.4-0.5 percent for smaller, vein deposits. Tungsten ores often contain other useful components (tin, molybdenum, beryllium, gold, copper, lead, and zinc). In addition, the wolframites of some deposits contain large amounts of tantalum and scandium, which can be extracted from them. To obtain concentrates containing 50-60 percent WO₃,  the ores are enriched using gravitational, flotation, and other methods of concentration.

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In June, 2012, shares of China's tungsten companies surged on Wednesday aftera revelation the previous day that the world's largest tungsten mine had been found in east China's Jiangxi province.

An 18-month prospection project uncovered a tungsten mine with 1.06 million tonnes ofconfirmed reserves in Jiangxi's Jiujiang city, according to a statement posted on the website ofthe Ministry of Land and Resources on Tuesday.

The mine is expected to have a potential value of over 300 billion yuan (47.6 billion U.S.dollars), the ministry said.

Boosted by the news, shares in Chongyi Zhangyuan Tungsten Co. soared by the daily 10-percent limit to 33.39 yuan (5.27 U.S. dollars) at midday on Wednesday. MinmetalsDevelopment Co. gained 4.35 percent to 26.36 yuan while Chenzhou Mining Group Co. added3.35 percent to 20.69 yuan.

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A collimator is a device that limits the radiation output of an X-ray source. Without a collimator, X-rays would escape which would flood the detector with radiation and prevent a clear image from being attained. Due to tungsten alloy material has high density, excellent radiation attenuation properties, and environmental friendly; an X-ray collimator can be made from tungsten alloy. Tungsten X-ray collimator can be commonly done by standing thin tungsten on end in a sequence over the detectors to limit scatter. Tungsten X-ray collimator can prevent cross talk between detector cards in a detector bank within a medical or security application. This allows tungsten X-ray collimator to be protected from scatter radiation and only detect the radiation striking the detector straight on.

The picture shows thin tungsten in X-ray collimator:

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Radiation shields help a temperature sensor accurately measure air temperature without the effects of direct radiation. Due to tungsten material has high density, excellent radiation attenuation properties, and environmental friendly; it is widely used to produce radiation shielding parts.Tungsten radiation shielding parts are made from high quality tungsten heavy alloys. Tungsten alloys are stable at high temperatures. You can use one-third less material than lead for the same energy-absorbing effectiveness.

Details of Tungsten Radiation Shielding Parts:

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Tungstate crystals are considered high-class scintillators to be used as detector material for high-energy radiation. These crystals are frequently used as references in measurements on new luminescent materials. In this paper, we present manufacturing process of nanocrystalline tungstate materials. Lead tungstate (PbWO₄), cadmium tungstate (CdWO₄), calcium tungstate (CaWO₄), and zinc tungstate (ZnWO₄) were synthesized via modifying sol-gel process. An advantage of the developed technology is the possibility of manufacturing tungstate powders in nanocrystalline state not only at elevated temperatures but at room temperatures as well. X-ray diffraction method, scanning electron microscopy, and thermal investigations were done to establish structural and morphological state of these materials. For reaching the most dispersible with the lowest agglomeration single-phase system of tungstate materials, there was an established optimal relationship between the system of starting reagents and solvents.

 

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Three topics are presented for discussion: Regarding the Edison lamp, the author presents several samples of what has been termed "Edison's X-ray lamp." This occasion is the first time that the lamp has been publicly exhibited. It is known that in connection with Mr. Edison's experiments with Roentgen rays, and in the construction of his fluoroscope, he experimented with thousands of chemical substances, and the substance which he found most suitable for use on the fluorescent screen was tungstate of calcium, which, together with barium platinum cyanide, constitute the substances most extensively employed in fluorescent screens. The author will operate one of the tubes that will serve to indicate to some extent the results of Mr. Edison's experiments in this direction. Regarding the Nernst lamp, the author presents tonight various types of American, English, German and Hungarian Nernst lamps, of both self-lighting and torch-lighting types. Some of the foreign types of lamps he described in detail in his article presented at the 151st general meeting of the INSTITUTE on Feb. 18, 1901; and the Westinghouse type of Nernst lamp has been presented by Alexander J. Wurts at the summer meeting of the INSTITUTE at the Pan-American Exposition at Buffalo. The author notes in passing the German Nernst lamps which are shown burning here this evening, and which are the latest types manufactured by the Allgemeine Electricitats Gesellschaft of Berlin. The large lamp containing the pendant conical heating coil is of a new type, which is here publicly presented for the first time. Finally, the author presents small quantities of radium being due to the interest which radium has excited in the scientific world, and as there are probably few in this audience to-night who have had an opportunity of seeing this remarkable, and up to the present time, exceedingly rare substance.

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An efficient phosphor can be prepared by a co‐crystallization of  and  . The fluorescence, exicted by either 2537Aå or cathode radiation, is that of a mechanical mixture of  and  . In the presence of tungstic oxide, the formation of  is greatly accelerated.

Determination of the pertinent compatibility tetrahedra in the system  revealed that the phosphor compositions lie in the sub ‐ tetrahedron  . X‐ray data showed that there was no solid solubility of  in  ; the fluorescence of  is adversely affected by  .

 

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A typical formulation and method of preparation is given for the calcium‐silicate‐tungstate (CST) phosphor. The wave length of the peak fluorescent emission of the tungstate phase is a function of its lead content. From spectral distribution of the emission of a CST phosphor, one can determine the lead content and the luminous efficiency to be expected from the tungstate phase. The effect of calcium fluoride as a batch addition in increasing average particle diameter of CST phosphor is shown.

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With regard to the determination of foreign elements in tungsten, cinchonine has been widely used as a precipitant of tungsten. This paper, however, deals with the flame-photometric determination of calcium in ammonium paratungstate (A. P. T.) by the following isolation procedure of tungsten. A. P. T. is dissolved in a mixture of conc. hydrochloric acid and hydrogen peroxide, and the solution is heated until the decomposition of hydrogen peroxide is completed, and tungsten is precipitated as hydrous tungsten oxide. Methyl alcohol is added to eliminate the adsorption of calcium on the precipitate, and to decrease the solubility of the precipitate, then the precipitate is filtered off, and calcium is analyzed flame-photometrically.

 

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