The causes of tungsten points’ ablation of car distributor as seen below:

7. Soft spring of tungsten points’ arm of distributor. If the tungsten points’ arm spring is much too soft, when the car operating at low speeds, the flashover condition remain normal; due to the high speed inertia effect of the engine, tungsten points’ closure is more slower when the car is operating at a high speed, and the off-fire phenomenon will occur, therefore, the car's exhaust pipe will issue a irregular sound like "sudden, sudden, sudden". Besides, tungsten points will appear rebound phenomenon after closing, and the appearance of spark will be more vulnerable, ultimately tungsten points will be ablated.

8. The ground capacitor is bad. Due to the weak spark, the flashover distance is shorter when test fire, therefore, when the engine is operating at no load, it will be more normal. But the car is instable in operation process, the carburetor will appear tempering phenomenon, and when the engine is working at high speeds, the exhaust pipe will sometimes shoot. So the arcs of tungsten points will increase, and ablate tungsten points eventually.

 

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 reasons of tungsten contacts ablation of car distributor as shown below:

7. The spring of tungsten contacts’ arm of distributor is too soft. If the tungsten contacts’ arm spring is too soft, flashover situation is still normal when the car running at low speeds; but when the car is working at a high speed, because of the high speed inertia effect of the engine, the closure of tungsten contacts is more slower, which appears off-fire phenomenon, so the car's exhaust pipe will issue a "sudden, sudden, sudden" irregular sound. Moreover, tungsten contacts after closure will appear rebound phenomenon, and the phenomenon make spark more vulnerable to emerge, and eventually tungsten contacts will be ablated.

8. Bad ground capacitor. When test fire, due to the spark is weak, and flashover distance is shorter, so the engine will be more normal when it is operating at no load. However, the car in working process is of instability, which would make carburetor appearing tempering phenomenon, and the exhaust pipe sometimes shooting when the engine is working at high speeds, make the arcs of tungsten contacts increase, eventually ablate tungsten contacts.


 

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

Spherical crystal ammonium paratungstate is an important raw material for preparing high density and high property tungsten alloy, tungsten oxide calcinated by spherical crystal ammonium paratungstate after hydrogen reduction has high apparent density, flow ability and even green density. It can be used to produce high property tungsten heavy alloy which has high density, tenacity and ductility. For example, W-Ni-Fe high density alloy produced by the spherical crystal tungsten powder which the fisher particle size is less than 200mm will has high density and tenacity.

The preparation of spherical crystal ammonium paratungstate is still under investigation. At present, the main technology for producing spherical tungsten powder is plasma condensation method. The equipment required for this method is complicated and the producing cost is very expensive. Producing efficiency is unsatisfied, thus it can not be used for industrial production which is only under experiment. The study on ammonium paratungstate is mainly focused on its particle size, particle size distribution, loose density and flow ability.


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 powder is a powdered with polygon particle shape’s metal tungsten, its physical characteristics are as follows: chemical formula: W, molecular formula: 183.85, particle size: 2-0.5um, 4-6um, bulk ratio: 2.5-3.0g / cc. Tungsten powder CAS registry number is: 7440-33-7, which is raw materials of tungsten processed materials, tungsten alloys and tungsten products. Tungsten powder for oxygen and impurities content has certain requirements and commonly used tungsten powder particle size is 2-10um of average fsss size. In addition, in the tungsten powder’s specific surface, bulk density, tap density, etc. are also change at certain range. Tungsten powder classification is based on the purity and particle size. The figure is based on different size of tungsten powder, which is divided into 14 levels.

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

 

Below are the affecting factors of spherical crystal ammonium paratungstate preparation:

1.Under low speed of stirring, granulation rate of ammonium paratungstate is lower. When the stirring speed reaches to 80-90r/min, the granulation rate is ideal. With the increase of stirring speed, the granulation rate falls down.

2.With the increase of crystallization temperature, the granulation rate of ammonium paratungstate falls down. Consider of production cycle, crystallization should be under 85 degree Celsius.

3.With the postponed of time for adding liquid material, the granulation rate of ammonium paratungstate goes up. Consider of fisher particle size, loose density, flow ability and uniformity of particle, liquid material should be added under the solution density 16Be.

4.With the increase of liquid material amount, the granulation rate of ammonium paratungstate gose up. It reaches the maximum level when the adding amount is one time more than the original value. As the adding amount increasing, granulation rate falls down.

5.With the raising of adding speed, the granulation rate also goes up. Consider of fisher particle size, loose density, flow ability and uniformity of particle, liquid material should be added every three hours.


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

Compared to traditional tungsten powder, preparation of fine tungsten powder can reduce sintering temperature. If the distribution of grain is close, structure of material after sintering will remain the nano-size.

A lot of researches have been done for super fine tungsten powder, like gas evaporation method, high energy ball milling; other method like control the hydrogen amount, temperature, adding dopant, etc. This method is easy to operate, low cost; the finished product is of high quality. Also yellow tungsten oxide, blue tungsten oxide, violet tungsten oxide is being used as raw materials to produce fine tungsten powder. Electrolyzation of tungsten oxide is also applied in the producing. But it is of high cost and low efficiency.

Ammonium paratungstate prepared by hydrogen reduction used to prepare tungsten powder is feasible. The ammonium paratungstate grain size is between 25-60um, which is not suitable for producing super fine tungsten powder. So the preparation of micron-sized ammonium paratungstate is the key problem.



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

The spectrophotometric determination of impurities in the ammonium paratungstate is mainly determined by the reaction temperature, reaction time, NaOH concentration and stirring speed on the active ingredients wolframite tungsten leaching. Also investigate the properties of the resin in the ion exchange process, the exchange of the solution before concentration and flow rate, desorbent concentration, flow rate and temperature and other factors on the impurity removal rate during crystallization temperature.

Ammonium paratungstate is an important raw material which is used as a source for high-purity tungsten oxides, tungsten metal powders, carbides, or as a laboratory reagent. Also tungsten powder including tungsten trioxide, tungsten blue oxide. Those powders are then used to make numerous products including wire, cutting tools, billets, welding electrodes, mining tools and many others. There are alloy series too, such as tungsten carbide alloy blade, alloy drill, alloy molds, etc.; and other wear, pressure, temperature and other machinery and equipment components. Also used in the manufacture ammonium metatungstate and other tungsten compounds as additives for the petrochemical industry. 



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 hexafluoride (WF6) is the A-level inorganic virulent, highly corrosive, strong irritant, if exposure to this product by careless may cause eye, skin and respiratory mucosa very serious burning. The US Occupational Safety and Health Administration regulations allow WF6 exposure limit of 0.2ppm. Workplace air fluoride hygiene standards (GB 16228-1996) provide the workshop air maximum allowable fluoride of 1.0mg / m3 (in fluorine). Health standard for tungsten in the workshop air (GB 16229-1996) provide workplace air tungsten maximum allowable of 6mg / m3. The following table is the relevant provisions of China's environmental standards.

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 hexafluoride (WF6) at different temperatures as a colorless, transparent bromine gas or liquid, the molecules have a symmetrical octahedron structure at room temperature. When it contact water it will quickly hydrolyzed and produce hydrogen fluoride and tungsten trioxide, so the tungsten hexafluoride has similar toxicity with HF in the air. Therefore, during the operation of tungsten hexafluoride the works should to wear chemical protection suits and wearing gas masks.
If during the operation the skin comes into contact with the tungsten hexafluoride should be stripped of contaminated clothing, rinse with running water. In the burning wound coated magnesium oxide ointment or glycerin dilute ammonia, and timely medical treatment. If eye contact with WF6 should immediately open the upper lower eyelid, with a large number of mobile water thoroughly washed after 15 minutes for medical treatment. If you are not careful inhalation, you should immediately from the scene to fresh air, if feel breathing difficulty should immediately oxygen therapy and go with medical treatment promptly and timely. If ingested, it will have to immediately mouthwash, drink milk or egg white, and timely medical treatment.

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 hexafluoride is a colorless gas or light yellow liquid. Solid tungsten hexafluoride is a deliquescent white crystal, smoke in the moist air. Its physical properties are as follows: chemical formula: WF6, molecular weight: 297.8, boiling point: 17.5 ℃, melting point: 2.3 ℃, relative density: 3.44, and it is soluble in most organic solvents, and react with hydrofluoric acid to generate H2. Its CAS registry number is 7783-82-6 CAS system.
It is a toxic gas, for humans and the environment has a certain impact. If it contact with moist air or hydrolyzed will emit toxic and corrosive hydrogen fluoride gas, such gas will cause eye, skin, and mucous membranes very serious injury. At the same time the gas is highly corrosive and can erode almost all metals, can rapidly corrode glass. For WF6 on-site emergency monitoring can use speed measuring tube method and particle-selective electrode method. And laboratory monitoring can use ion selective electrode method and membrane fluoride ion selective electrode method.

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