The content of tungsten in the Earth's crust is 0.007%. According to the data released by USGS in 2014, global tungsten reserves are around 3.5 million tonnes. About two-thirds of the world's tungsten resources are in the form of scheelite, and one-third are in wolframite-group minerals. The tungsten ore resources country distribution in the world is as follows:

According to the data released by USGS in 2014, world tungsten reserves are round 3.5 million tonnes. Tungsten resources are concentrated in China (1,900,000 metric tonnes), Canada (290,000 metric tonnes), Russia (250,000 metric tonnes), United States (140,000 metric tonnes), Bolivia (53,000 tonnes), Austria (10,000 metric tonnes) and Portugal (4,200 metric tonnes).

Tungsten Powder Manufacturer & Supplier: Chinatungsten Online - 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

About 20 species of tungsten minerals are known, of which wolframite [(Fe, Mn) WO₃] and scheelite (CaWO₄) have industrial value.Tungsten ore grade mined in 70s, more between 0.2 ~ 0.5% WO₃, can get containing tungsten trioxide 60 to 70 percent or higher grade tungsten concentrates after dressing. China's tungsten ore reserves account for more than half the world's total reserves, mainly in Hunan, Jiangxi, Guangdong and Fujian provinces. In 1979, the world's major tungsten producing countries (except China) of tungsten ore reserves and production in the following table: 



 

Tungsten Powder Manufacturer & Supplier: Chinatungsten Online - 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

Tungsten copper points, which can be applied to control the current of the switch, and mainly play a role in relays, contact switch, breakers, magnetic motors and other parts, also namely tungsten copper electrical points. Points properties will directly have an effect on the work of the entire electrical system, particularly communication system, modern automatic control system and other large power system, the system will work in a mess or even can’t run if one or more points in them, whose properties derogate, so, the work properties of tungsten copper points should be improved.

Properties requirements of tungsten copper points can be seen as below:
1. Require the points owning good electrical conductivity and nice thermal conductivity to reduce heat loss and the tungsten oxide on the surface of points;
2.Require points material having high boiling point, high melting points, high melting heat and evaporation heat  to reduce contact wear and the occurrence of welding of the points under the arc / spark action;
3. Require the point having stable chemical properties, stable contact resistance, and small change of contact resistance when it being polluted by the environment;
4. Require the points possessing appropriate elasticity and hardness, the contact area would be small when the hardness is too large,  due to bounce between the points, the wear will increase when the flexibility is greater;
5. Own the properties of easy machining and welding;
6. The price is lower.



 

Tungsten Metals Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten.com.cn
 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

There are many factors on tungsten copper contacts, among which the main factors are structure size of the contacts, the manufacturing process, the particle size of tungsten powder, applications occasions, current properties and the breaking speed of contact and early pressure and so on. " Factors on Tungsten Copper Contacts - Structure Size and Manufacturing Process" which focuses on the factors of structure size and manufacturing process, and this article will introduce the factors of tungsten powder particle size, applications occasions, current properties and the breaking speed of contact and early pressure:

3. The tungsten powder particle size. Studies have shown that, whether it is with a thicker tungsten powder or thinner tungsten powder to prepare a contact material, their anti-arc erosion performance is not very good, but if prepare the contact by mixing the coarse powder and fine powder at a certain percentage, then the performance of tungsten copper contacts are relatively better. Note items: if the components of the contact material are different, then their mixing proportions are also different.

4. Applications occasions. The experimental results show that for different applications occasions, different components of the contact have its corresponding optimal application occasions. For example, in air or a vacuum switch, tungsten (90) / copper (10) its performance against arc erosion is the best.
5. Current properties. Studies have shown that if the properties of the current are different, and then its on-off process will produce different transient properties, however, after selecting the contact, its value is constant.

6. The breaking speed of contact and early pressure. Arcing time is determined by breaking speed especially early opening rate; arcing time can be shortened by increasing the early speed to achieve it, so that the possibility of contact ablation reduced. If the early pressure is increased, the mechanical vibration of the contact can be reduced, so that the arc erosion and mechanical wear is reduced.

 

Tungsten Metals Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten.com.cn
 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

Factors on tungsten copper contacts can be seen from the following main points:

1. The structure size. In theory, if the structure size of tungsten copper contacts is larger, then its anti-arc ablation performance will be stronger, because its use of energy more dispersed. In actual use, because the limit size of electrical switch structure, its size can not do much. In recent years, someone has developed plug-in contacts, hollow contacts, not only accelerates the speed of heat dissipation of contact materials, but contacts can still maintain good contact state after the ablation.

2. The manufacturing processes. Now manufactures in China are commonly applying infiltration method (mixing powder, pressing, sintering) to prepare tungsten copper contacts. What is different is that whether there is the use of sintering tungsten skeleton infiltration process. Compared with the performance of tungsten copper contacts, the ones used the process for the preparation is more ideal than the other ones without using it. In recent years, foreign countries have adopted more advanced preparation technology to improve the life of the contacts, such as, arc melting, sintering rolling process, fiber-reinforced method and so on, but China for the use of these new processes are still in the laboratory stage.

 

Tungsten Metals Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten.com.cn
 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

Tungsten copper alloy having a high density, high strength, high temperature resistance, microstructure uniformity, resistance to arc erosion and other characteristics, and its electrical conductivity and thermal conductivity are good. It is widely used, mainly in microelectronics materials, EDM electrode, military high temperature resistance materials, high-voltage switch with electrical alloys, as parts and components are widely used in aerospace, power electronics, machinery, metallurgy, sports equipment and other industries.

Tungsten copper contacts combined with excellent characteristics of the metal tungsten and copper. Among them, tungsten owns high melting point, high density; copper owns superior conductive and thermal performance.
The melting point of tungsten: 3410 ℃; the melting point of copper: 1080 ℃;
Tungsten density: 19.34g / cm3; copper density: 8.89 g / cm3;
Tungsten copper alloy composition range: WCu7 ~ WCu50.

Injection molding is relatively common method of making tungsten copper alloy. Tungsten copper contacts prepared by injection molding method: mixing copper tungsten powder with uniform particle size of 1-5 microns and nickel powder or iron powder with tungsten powder with a particle size of 0.5-2 micron and tungsten powder with a particle size of 5 -15 microns, and then entering into the 25% -30% of the organic bonding agents (such as paraffin or polymethylmethaerylate) for injection molding, then using steam cleaning and irradiation method to remove the binder, sintering in hydrogen, finally to obtain tungsten copper alloy with high density.

 

Tungsten Metals Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten.com.cn
 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

The physical properties of tungsten strontium as follows: chemical formula: O4SrW, molecular weight: 335.4576, relative density: 6.187, it can decompose in acid, but insoluble in ethanol and other organic solvents. It is stable at room temperature and atmospheric pressure, but to avoid in contact with material, oxide and halogen. Tungsten strontium has some pollution to water, undiluted or large quantities of tungsten strontium can not to reach ground water, water course or sewage system, what’s, more without the relevant government departments permission can not allow material to be released to the surrounding environment. In addition, tungsten strontium has some toxicity and irritation, during the operation to do some protective measures: such as wearing goggles, gloves, and protective clothing. While avoiding eye and skin contact with the product.

Tungsten strontium preparation methods are the following:
1. To obtain it from the alkali metal and tungstate metathesis reaction.
2. Melting tungsten trioxide and metal oxide to produce tungsten strontium.
3. Take it by melting tungsten trioxide and carbonate.

Tungsten 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

 

Silver tungstate is a pale yellow crystal or powder, its Chinese alias is strontium chloride or strontium dichloride. There are some physical properties of silver tungstate as shown in the following: molecular formula: Ag2O4W, molecular weight: 463.574, it can be dissolved in nitric acid, ammonia and potassium cyanide solution. And the chemical properties of it are as follows: silver tungstate easily reduced, but it is not strong oxidant; it is easy to generate tungsten sulfide when it react with hydrogen sulfide, besides, it can broken down into white hydrated tungtsate by reacting with nitric acid. Silver tungstate is mainly used in catalysts, electronic and chemical industries. It can be produce by reacting sodium tungstate and silver nitrate, or get it from tungsten trioxide and silver oxide reaction. To store Ag2O4W in somewhere is at room temperature, cool and dry with closed.

Ag2O4W related systems number as follows: CAS registry number: 13465-93-5, MDL number: MFCD00014147, EINECS number: 236-708-3, PubChem number: 24881171. Also silver tungstate have a certain toxicity and irritation, so when operation to wear protective gloves, goggles and protective clothing to avoid contact with the eyes and skin products.

Tungsten 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

Tungsten polymer material is a special blend of shielding material moderates and attenuates both fast and intermediate neutrons while eliminates primary and secondary gammas. 80-95% reductions in exposure rates have been achieved in field applications.

Tungsten polymer radiation absorption ability:

• Gamma rays – Very penetrating and are best stopped or shielded by dense materials, such as lead or uranium. Gamma rays are similar to x-rays.
• HVL (Half Value Layer) – the amount of shielding material to achieve 50% reduction in dose rate
• TVL (Tenth Value Layer) – the amount of shielding material to achieve 90% reduction in dose rate
• Radioactive Source – the radioactive element (e.g. Co-60)
• Attenuation – the reduction in dose rate. (Eg., HVL or TVL)

  Tungsten Alloy Manufacturer & Supplier: Chinatungsten Online- http://www.tungsten-alloy.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