Tungsten carbide burs are used to deal with cutting, shaping, grinding and removing the sharp edges, burs and excess material in practices and end mills for metalworking as well as for holes of all sorts. During the operation, for the safety consideration, here are some usage recommendation to review.



1.Make sure the bur shank is always well inserted int o the collet, and it is clamped down tightly enough.

2.Ensure the pressure is light and always ensure the bur moving focusing on the highest material first.

3.Make sure the work piece and the work bench is well secured.

4.Ensure the burs don't snag or jam into the work.

5.Always wear eye protection as a bottom line, whereas a full shield for face is recommended.


Tungsten Carbide Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-carbide.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

Co-precipitation method is to add a suitable precipitant in a mixed metal solution, a homogeneous precipitation reaction product. It is an important method for produce ultrafine tungsten oxide which including two or more metal elements. using co-precipitation method producing tungsten trioxide, first step is taking 1mol /L Na2WO4 solution and Na2SnO4 solution slowly drop after mixing to dilute H2SO4 in boiling, stirring constantly generate precipitation. Then after aging, washing, filtering, drying and calcining to obtain SnO2-WO3 gas sensing powder materials. The study found the addition inhibited the growth of SnO2 WO3 grains, increase the sensitivity of its gas, wherein the doping amount of 0.5% is optimum.

Some researchers also use Sol-co-precipitation produce tungsten trioxide, in WCl6 and TiCl (4wt %) aqueous solution adding ammonium hydroxide and suitable surfactants to formW (OH) 6 and Ti (OH) 4, then after centrifuged and calcining to obtain the tungsten trioxide powder in 3 ~ 9nm. The study found that the smaller the particle, the more uniform particle size. Agglomeration, the higher the sensitivity of the respective gas and recovery time is shorter accordingly.

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

 

Study on magnetic properties of tungsten trioxide material no much better than the electrical and optical properties. But the object of study the magnetic properties of tungsten trioxide are mainly to clarify their electronic structure and electrical transport properties through the relevant magnetic measurements. After the study of the magnetic properties of WO3-X, researchers found that such materials have Pauli paramagnetic type, and further consider the impact of structural factors may be. By measurement magnetic and electrical parameters, the researchers believe the simple quasi-free electron gas model uniformly distributed in the lattice can explain the observed magnetic behavior. Researchers studied with crystalline structure of the low-temperature paramagnetic WO3 found until the ultra-low temperature of the sample 9 × 10-5K did not appear superconductivity, showing a magnetic behavior.

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

 

Structure of tungsten trioxide can well be described as a common apex WO6 octahedron three-dimensional network structure. However WO3 symmetry relatively quite low because it is a modification by ReO3 ideal structure, embodied in WO6 octahedra tilt and tungsten atoms replacing the central position of the octahedron. The various change of phonon lattice and electronic structure let tungsten trioxide produced several crystalline phase, these types of crystalline phases with increasing temperature is evolved from the low to the high symmetry change.

After the studies, now researchers get more recognized tungsten trioxide phase change order: monoclinic Pc (ε-WO3) → triclinic PT (ζ-WO3) → monoclinic P21 / n (λ-WO3) → orthogonal Pbcn (β-WO3) → Quartet P4 / ncc (α-WO3) → P4 / nmm. In 2002, after continuous research, found new crystalline phase. Also through high resolution neutron powder diffraction method confirmed the existence of a new phase in the monoclinic temperature zone of 720 ℃ to 790 ℃.

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

 

Solid-phase method is blending a proportion of metal salt or metal oxide, calcined after grinding. According to studies, calcined APT under different conditions will obtain different structure tungsten trioxide. Using ammonium tungstate (NH4) 2WO4 as raw materials producing tungsten trioxide by solid phase out method the reaction condition different the WO3 structure is different. A certain amount of (NH4) 2WO4 calcined for 3 hours at 600 ℃ condition, and cooled to obtain WO3 powders which is monoclinic and triclinic two crystal phases. Or using (NH4) 2WO4 as the raw material by calcination, low temperature hardening and calcination, nature cooling method for preparing monoclinic phase and quadrature phase of WO3 respectively. Found that higher activity quadrature phase WO3 than monoclinic WO3. While changing the calcination temperature to 700 ℃ to resolve (NH4) 2WO4 producing WO3 catalyst. After studies theWO3 catalyst in electron acceptor Fe3 + solution system photocatalytic activity found that the increasing of Ar content, the WO3 catalyst surface oxygen vacancies increase, catalytic oxygen evolution increases. And in pure Ar conditions it has been the most active WO3 catalyst.

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

 

After the study found that tungsten trioxide producing method, reaction conditions, there will affect the structure and properties of the product. At the same time, the different precursor also has some impact on producing WO3. Depending on the reaction environment of raw materials, methods for producing WO3 can be roughly divided into solid, liquid and gas phase method.

Solid-phase method is a traditional powder technology, using solid-phase for producing tungsten trioxide is usually obtained by calcination APT, but due to different firing conditions there was not the same reactant. Such as at 400 ℃condition calcinate APT with oxidizing atmosphere will obtain an orange powder. And it is characterized by XRD as black bronze (NH4) 0.33WO3 which also contains sixty WO3. Continued calcination at 500 ℃ for 2 hours, the resulting yellow-green product, XRD characterization of monoclinic WO3. In at 400 ℃ with reducing atmosphere calcined APT will obtain blue tungsten oxide. It is a mixture of bronze ATB, WO3, WO2.9, W2.72, W3O other phase composition.

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
 

Tungsten trioxide molecular weight is 231.85, the theoretical density of 7.16g / cm3, insoluble in water, soluble in acid, slightly soluble in HF, soluble in hot alkali, ammonia. Outer electron structure of tungsten is 5d⁴6s², and therefore the compounds may be presented  +2, +3, +4, +5 and +6 valence state, but different valence states coexist kind of this situation often occurs. Tungsten trioxide is the highest price of tungsten oxide. The oxygen content of WO3 is not usually meet stringent stoichiometric ratio so using WO3-X to represent the type. Because there is different degrees oxygen deficiency, making some W6 + ions are reduced to W5 + ions, forming five or six price of tungsten oxide mixed valence state. After studies, in fact, and W5 + W6 + is present in all of the crystalline tungsten oxide. For example: W18O49 (= WO2.72) can be expressed as W86 + W105 + O49 of patterns. Dopting in WO3-X were pentavalent oxides (such as Nb2O5) can make tungsten in the highest valence state. Under certain conditions, it may be the presence tetravalent oxide of tungsten.

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
 

Compare APT and H2WO4 as raw material producing tungsten trioxide (WO3-X) photocatalyst found that different performance WO3-X photocatalyst produce by different materials. After further studies found that different performance WO3-X photocatalyst obtained from different producing methods.

Using solid phase method and the H2WO4 as raw material the production of WO3-X photocatalyst are monoclinic.  Photocatalytic performance influence by temperature was very little. And there have been sixty thousand phase and orthorhombic in the WO3-X which is produced by hydrothermal synthesis method. Oxygen index is 2.50 and photocatalytic performance has been greatly improved. The product of hydrothermal synthesis method 24 hours reaction has highest rate of photolysis. At 365nm ultraviolet light, oxygen production rate arrive at 140umol / L / h O2. However, hydrothermal method, with the reaction temperature, the raw material has undergone transformation which is orthogonal WO3-X • 0.33H2O → sixty thousand WO3-X → monoclinic WO3-X's. Photocatalytic performance will continue to reduce when the WO3-X sixty phase content continue to reduce.

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
 

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