Since the price state of tungsten trioxide changes largely, and it is difficult to determine the oxygen content, structure phase changeable and electrical properties and complex reasons, the photocatalytic properties of different crystalline WO3-X has not be determined. After a lot of research found different materials and different producing method synthesized different WO3-X and the structure and photocatalytic performance are different. Firstly, using solid phase method to sinter WO3-X photocatalyst and APT is raw material. It is mainly monoclinic phase. When the treatment temperature is 600 ℃, the processing time is four hours, there have been sixty thousand phase WO3-X, oxygen index of 2.44, water photolysis rate is the highest. At 365nm ultraviolet light, oxygen production rate is 148.8umol / L / h O2. Then compare using H2WO4 as raw materials by solid phase method to sintering WO3-X photocatalyst. Using this method producing WO3-X photocatalyst is monoclinic phase, but temperature had little effect on the photocatalytic decomposition of water properties.

Tungsten Manufacturer & Supplier: Chinatungsten Online - http://www.chinatungsten.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 tungsten crucible owns a particularly high density and purity. By correctly filling the mold used for the crucible and carefully controlling the temperature distribution during sintering, to achieve uniform wall and base thicknesses - an important prerequisite in achieving the high level of creep resistance that characterizes our crucibles.

During sapphire production, Al2O3 - the compound that is to become the future single crystal - is melted in molybdenum and tungsten crucibles. It is in the process that pressed-sintered crucibles show their strengths to best effect. They are repeatedly heated to more than 2 000 °C (3632 °F) and then cooled down again. This process, which would cause fissures and distortions in other materials, is not a problem for PLANSEE products. 

If the surface of the crucible is too rough, the sapphire cannot be released or can only be partially released from the wall of the crucible, which results in cracks and faults in the crystal. Not only that: The crucible itself is also damaged in the process and has to be reworked or replaced earlier than planned.

Our pressed-sintered crucibles made of tungsten have a surface roughness of less than 0.8 µm. The sapphire can be extracted from the crucible without difficulty and without damaging the surface of the crucible. For the sapphire producers, this results in fewer complexes and expensive reworking of the surface of the crucible. The cycles run smoothly and deliver high-quality ingots. And there's another advantage: The smooth surface is less susceptible to corrosion caused by the aggressive melted sapphire. This increases the service life of the reusable tungsten crucibles.

 

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 crucible’s general use specification requires thickness is between 6 mm-10 mm, is also a thin-walled crucible. Because of the brittleness of tungsten, so its process is only by a simple hand-shaping, and can not be lathe shaping. Thus, the thickness after pressing determines the thickness of the product. Therefore, the choice of latex coat diameter should be larger than mandrel of 6 mm-10 mm.

If the selected latex coat is too large, it will lead to the gap between mandrel and latex coat is too big, because the tungsten powder particles are relatively large and heavy, while the thickness of the latex coat itself is also between 2 mm-4 mm, which will lead to excessive loading weight and thick walls. The chosen of seal size is: 4 mm smaller than the inner diameter of mandrel and a thickness of 8 mm-10 mm. If you calculate sintering shrinkage by a rate of 12% -16%, the wall thickness after pressing should be around 8 mm-12 mm.

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 key of tungsten crucible forming lies that mandrel design is reasonable. If the mandrel design is unreasonable, not only the core module will be deformed, but also the transition portion of the crucible bottom and the crucible wall will crack. Therefore, the choice of the wall thickness of the mandrel should be able to withstand a certain degree of strength. In order to prevent the phenomenon that tungsten crucible suffers the stress focused on the transition area at the bottom and walls in the pressing process, for this part, it is need to adopt arc transition. If this transition is too small, tungsten crucible after molding, this site will has a small crack propagation source, and may make the bottom and the wall at the site off. Further, for demoulding, the top and bottom of the mold should have a certain slope.


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 crucible has a wide range of applications in vacuum sintering, electron spraying, rare earth smelting, crystal growth and other industries. Because tungsten is expensive and its working conditions are harsh, it is especially important to improve its reusability.

Compare of tungsten crucible molding method:

According to different molding process (manufacturing method), tungsten crucible can be divided into different types: pressing forming type, sintering molding type and welding molding type.

In these products, welding molding tungsten crucible has the advantage of a relatively low price, and because of the increase of its thickness, compared pressing molding tungsten crucible, it has longer service life. Of course, such a tungsten crucible durability depends on, the selection of materials, welding environment, welding technology and appropriate heat resistance treatment after forming. If these processes are dealt with appropriately, sintering tungsten crucible and welding tungsten crucible with the same thickness will has the same high temperature resistance performance and service life, and sometimes even the life of welding type is above the sintering one.

Pressing molding tungsten crucible is most widely-used, whose application is most extensive and it is relatively inexpensive. However, due to the production process, it has a drawback: thin. Thus, long-term use performance of such crucible is poor.


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

A way to extract jammed sapphire ingot from the tungsten crucible, its process steps and controlling technical parameters are as follows:

Preheat( hydrogen peroxide): pour industrial pure or analytical hydrogen peroxide into the beaker, and then place the beaker on the electric heater, and then heat it until the temperature is up to 50-70 ℃;

Soak the inner wall of the tungsten crucible(heated hydrogen peroxide): pour the heated hydrogen peroxide into the tungsten crucible continuously, until the hydrogen peroxide submerged the ingot jammed position; wait the reaction of hydrogen peroxide with the inner wall of the crucible for 6-8 hours, observe the color and surface state of hydrogen peroxide, when the color is yellow-green, and there is no bubbles emerged from the water level , then pour out of the liquid, after that, pour heated hydrogen peroxide into the tungsten crucible once again, repeat 3-4 times;

Extract jammed sapphire ingot from the tungsten crucible: use a copper braid to tie the jammed sapphire ingot, with the use of mobile Stacker and take the chain to extract the jammed sapphire ingots;

Subsequent processing: after extracting jammed sapphire ingot from the tungsten crucible, using lathe to processing tungsten crucible inner wall, in order to remove the deformed portion of the inner wall of crucible of tungsten; ensure crucible is no more jammed in the subsequent use.


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 crucible is tungsten product, which is made by many different ways, such as, by pressing molding, welding molding, sintering molding, spinning molding, tungsten bar molding, etc. or using pure tungsten plate, tungsten sheet and pure tungsten bar to processing through the appropriate process. Among them, tungsten bar molding method is unusually used. Such tungsten crucible mold is crescent-shaped, usually 1/4 of the arc, the pressing out curved tungsten, after sintering, its surfaces is presenting metal silver when it is taken out of the sintering furnace, which can be used directly. Then accumulating and folding the sintering tungsten crucible, and then welding the middle crack. Tungsten crucible made by this way, whose structure is more scattered, and the surface is not flat, but after polishing, it may be rounded.

Tungsten crucible features:
Wear resistance;
High temperature resistance;
Corrosion resistance;
Low expansion characteristics at high temperatures;
Purity: W≥99.95%;
Density: ≥18.2g / cm3;
Application temperatures range: 2000-2400 ℃.

Tungsten crucible applications:
Because tungsten crucible melting point is up to 3410 ℃, and its excellent and various performance, tungsten crucible is widely used as a core container for quartz glass melting furnace, sapphire growth furnace, rare earth smelting furnace and other industrial furnace, it can also be used for electronic spraying.

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

Sintering tungsten crucible uses a crucible-shaped mold to press out of the crucible, and then by sintering. After sintering it, by polishing it, to ensure its smooth surface finishment, and has a metallic luster. Surface finishment can be controlled at Ra1.6um.

Sintering tungsten crucibles’ tungsten purity is above 99.95%, and a density of 18.2g / cm3. Sintering tungsten crucible height can reach to 850mm, maximum diameter can be 500mm, the wall thickness is between 8 ~ 12mm. Sintering tungsten crucible diameter and height tolerance can be controlled within +/- 0.5mm. Sintering tungsten crucible is mainly used for Sapphire furnace, to produce wafers.

Tungsten crucible performance:

Tungsten crucible performance mainly has the following points, wear resistance, high melting point, high boiling point, corrosion resistance, high temperature resistance, high thermal conductivity; good harden ability, low expansion characteristics at high temperatures.

Tungsten crucible purposes:

Tungsten crucible is widely used in crystal growth, rare earth smelting, electronics coating, quartz glass and other industries.


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 crucible is a vessel or melting pot, whose shape is similar to the pot or cup, which is also a kind of crucible and is made of extremely refractory material (such as graphite, quartz, clay, china clay or compare refractory metal, etc.) .

Crucible is a bowl-shaped vessel, which has a ceramic-like deep bottom. The following is something about the use of crucible in lab. Because crucible’s high temperature resistance performance is better than glass crucibles’, so when there is a solid requires heating or melting, we must use it. When using a crucible, in order to prevent heat objects bounces or melting liquid spills, a crucible cover is usually needed to diagonally cover on the crucible, to allow air to have a freely access and for possible oxidation reactions. Because the bottom of the crucible is very small, generally you need to put it on the pipeclay triangle and then directly heat it. Crucible can be positively or obliquely put on the pipeclay triangle, according to the requirements. After heating, the tungsten crucible should not immediately be placed on a cold metal table, to prevent it from being broken due to the rapid cooling.

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

Due to tungsten alloy has excellent radiation attenuation properties, with thinner thickness but high effective in blocking harmful X-ray and gamma radiation, , it is widely used in multileaf collimator. During radiotherapy, tungsten multileaf collimator are delivered while the gantry rotates around the patient. The intensity of the radiation is modulated and the shape of the beam is dynamically adjusted by moving the tungsten alloy leaves. The gantry speed and dose rates may also be changed during the rotation. This provides the potential to create effective treatment that are high standard with a shorter treatment time.

  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