The presence of a peak centered near m/z 2862, observed for the first time for the caged dodecatungstate radical-anion, [W₁₂O₄₁]^−∙, enables distinguishing WO₂ from WO₃ by Laser Desorption Ionization mass spectrometry (LDI-MS). In addition to WO₂, laser irradiation of dry deposits made from aqueous ammonium paratungstate, and calcium and lead orthotungstate also produce the [W₁₂O₄₁]^−∙. In contrast, spectra recorded from deposits made from aqueous Na₂WO₄, sodium metatungstate, and WO₃, or non-aqueous calcium and lead orthotungstate, and ammonium paratungstate, failed to show the m/z 2862 peak cluster. These observations support the hypothesis that polycondensation reactions to form [W₁₂O₄₁] occur solely in the presence of water. Although dry spots are irradiated for ionization, the solvent used for sample preparation plays an important role on the chemical composition endowed to ions detected. For example, the m/z 2862 peak seen from deposits made from aqueous ammonium paratungstate, and calcium and lead orthotungstate, is absent in the spectra recorded either from pristine deposits or those derived from solutions made with organic solvents such as acetonitrile or ethanol.

Tungsten Powder Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-powder.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
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

Self-organized and highly ordered titanium dioxide (TiO₂) nanotubes synthesized through anodization and wet impregnation were applied to incorporate tungsten trioxide (WO₃) species uniformly throughout the walls of nanotubes. In this study, ammonium paratungstate (APT) was used as a precursor. The effect of APT molarity on the formation of WO₃–TiO₂ nanotubes was investigated using field emission microscopy, energy dispersion X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, photoluminescence, and X-ray photoelectron spectroscopy. The WO₃–TiO₂ nanotubes dipped in 0.3 mM APT aqueous solution exhibited better photoelectrochemical water-splitting performance under visible illumination. A maximum photocurrent of 2.1 mA/cm² with a photoconversion efficiency of 5.1% was obtained, which is approximately twice higher than that of pure TiO₂ nanotubes. The findings were mainly attributed to higher charge carrier separation, which minimized the recombination losses and enhanced the transportation of photo-induced electrons in this binary hybrid photoelectrode.

Tungsten Powder Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-powder.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
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 nanosized powders have been synthesized via a single-step pathway by the RF induction thermal plasma process using APT (ammonium paratungstate) as the precursor. The effects of powder feeding rate and quenching rate on the phase and particle size of the resultant powders were investigated. The phase composition, morphology and particle size distribution of the tungsten nanosized powders were characterized by X-ray diffraction (XRD), field-emission scanning electron microscope (FESEM), and transmission electron microscopy (TEM). The results showed that the crystallized product is spherical tungsten nano-powder with a particle size of less than 50 nm. Moreover the particle size of the tungsten nanosized powders was successfully controlled by adjusting the quenching rate in RF induction thermal plasma system.

Tungsten Powder Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-powder.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
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 oxides (for example, WO2 and WO3, respectively known as blue and yellow tungsten oxide) is a naturally occurring material used in the manufacture of tungsten. Significantly for the purposes of the present invention, tungsten oxide has lower density and less electrical conductivity than pure tungsten metal. These properties present distinct improvements in the X-ray and gamma ray source shielding area, in which electrical conductivity is a disadvantage. Ammonium paratungstate and ammonium metatungstate (respectively 5(NH4)2O.12WO3.5H2O and 3(NH4)2O.12WO3.XH2O) may also be advantageously employed, as may a range of other tungsten precursors. Ammonium paratungstate has a WO3 content of 88.5%, the WO3 of ammonium metatungstate obviously depends upon the water content. In the case of the ammonium tungstate precursors, removal of the ammonia groups generates WO3, and this same process may be used with other tungsten precursors, or the additional groups may be used in the composite.

Tungsten Powder Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-powder.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
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

In W-ThO2 based alloy, the addition of an appropriate amount of thermal stability of ThO2 particle dispersion, can not only reduce the electron work function, can also inhibit the grain growth of tungsten, the material has a high recrystallization temperature, excellent high temperature strength and creep resistance. Tungsten thorium alloy is not only a hot electron emission material widely used, and is excellent in the electrode material.

Tungsten-rhenium alloys, rhenium addition, not only can improve the strength of the material, improve the recrystallization temperature of the alloy is about 200 ~ 400 ℃, the secondary recrystallization plastic, grain growth is slow, and can significantly reduce the plastic - brittle transition temperature . Adding more than 30%, such as rhenium, it will damage the workability of the alloy. Tungsten-rhenium alloy also has a high thermoelectric power, at 2200 ℃, thermoelectric power and temperature into a linear relationship. Tungsten-rhenium thermocouples measure temperatures up to 3000 ℃, is an excellent high-temperature thermocouple material.




Tungsten Powder Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-powder.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
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
 

Single TIAiN many types of coated tungsten carbide cutting tools, there TiC coated tungsten carbide cutting tools, TiN coated tungsten carbide cutting tools, Al2O3 coated tungsten carbide cutting tools, TIAiN coated tungsten carbide cutting tools. Compared with other coated tungsten carbide cutting tools, TIAiN coated tungsten carbide cutting tools with unique superiority.

TiAlN coated tungsten carbide cutting tools excellent oxidation resistance, coating material begins to decompose higher temperature than other coatings, this feature allows the tool from heat hazards, thus protecting the cutting edge. TiAlN coated tungsten carbide cutting tools for mold finishing, without cutting fluid situation, TiAlN coated tungsten carbide cutting tools can speed cutting of hardened steel, which is not affected by the cutting heat generated. TiAlN coated tungsten carbide cutting tools price than other high coating knife about 30%, while life can be increased 3-4 times. Although TiAlN coated tools have high thermal stability, but if the work in the tradition of cutting parameters, its life than ordinary TiN coated tungsten carbide cutting tools length, only at high speed cutting conditions, in order to significantly improve its service life .


 

Tungsten Carbide Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-carbide.com.cn
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
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

In several common coating (TiC, TiN, Al2O3, TIAiN), and because of their different properties, it is suitable for different processing conditions. When the low-speed cutting steel material, TiC, TiN coated tool compared with Al2O3 coated tungsten carbide cutting tools is good, it is because in this cutting conditions TiC, TiN coated tungsten carbide cutting tools in the anti-flank terms of wear and resistance to mechanical vibration better than Al2O3 coated tools.

In contrast, in the high-speed cutting Al2O3 coated tungsten carbide cutting tools are better than TiC, TiN coated tungsten carbide. When the temperature is high speed cutting cutting tool wear by friction, diffusion and oxidation caused, Al2O3 coated tungsten carbide has good chemical stability and high temperature oxidation resistance, and therefore anti-crater wear when its temperature, After the anti-flank wear, anti-edge plastic deformation are better than TiC, TiN coatings, carbide high durability.
In continuous cutting conditions, the wear resistance and heat resistance are the main factors affecting the tool life, Al2O3 coated tools have excellent oxidation resistance and high temperature hardness, so the cutting conditions under continuous performance is better than TiC, TiN coating. But under intermittent cutting conditions, due to an impact force, the toughness of the coating has become a major influence carbide durability factor, but poor toughness Al2O3 coated tools, impact resistance is far better than TiC, TiN coated layers.


 

Tungsten Carbide Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-carbide.com.cn
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
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

According to different uses, tungsten alloys are divided into tungsten carbide, heavy alloy, metal sweating materials, contact materials, electronic and electric light materials.

Tungsten doped tungsten powder is added in about 1% of silicon, aluminum and potassium oxide, in a sintered (since resistance sintering) process, volatile additives hydroxide, the formation of pores within the material, pores after processing edge axially elongated; after annealing, diffusion of pore-forming elongated parallel to the wire axis line of bubbles, this dispersion of bubbles bubble known as potassium.

Potassium tungsten bulbs impede lateral grain grow and improve high-temperature tungsten sag performance, but also to improve the room temperature ductility after recrystallization, help around the wire and transportation and storage. China doped tungsten values are in accordance with the high temperature creep WAl1, WAl2, WAl3 three kinds of grades.




Tungsten Powder Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-powder.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
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 carbide cutting tools in high-speed cutting, the blade tip temperatures up to 900 ° C, this time tungsten carbide cutting tools cutting tools wear is not only a mechanical friction and wear (behind the main form of tool wear), and adhesive wear, diffusion wear and oxidative wear (mainly in the form of the tool edge wear and crater wear), so that the cutting process can be considered as a process of physical and chemical changes of a micro-region.

Titanium tungsten carbide cutting tools is a high hardness and wear-resistant compound, has a good anti-friction and wear properties; titanium nitride lower hardness, but have a high chemical stability, and can greatly reduce the friction between the tool and the workpiece to be machined factor. From the coating process considerations, both of which are desirable coating material, but regardless of titanium tungsten carbide cutting tools or titanium nitride coating material, a single coating layer are difficult to meet the high-speed cutting tool coatings on integrated requirements. Antioxidant and anti-wear performance diffusion wear, no material can be compared with alumina (Al2O3). However, due to physical and chemical properties of the alumina matrix material with much difference, can not be made of a single alumina coating preferably coated tools. Emergence of multi-layer coatings and related technology, the coating and the substrate material can improve bond strength, while overall performance with a variety of coating materials.



Tungsten Carbide Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-carbide.com.cn
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
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

CVD technology since the late sixties, the coated tungsten carbide cutter has been very widely used. In the CVD technique, the preparation of the required metal source vapor deposition is relatively easy to achieve TiN, TiC, TiCN, TiBN, TiB2, Al2O3, such as single and multi-multi-layer composite carbide coating, the coating and substrate high strength, a film thickness of up to 7 ~ 9μm, CVD coating has good abrasion resistance.

In the late eighties, the United States 85% of tungsten carbide cutting tools with a coating, wherein the CVD coated tungsten carbide cutting tools accounted for 99%.

The mid-nineties, CVD coated tungsten carbide coated tungsten carbide inserts in the tool still account for more than 80%. For example, using the CVD method TiC single coat of WC-based cemented carbide substrate YW1 / TiC, and uncoated WC-based cemented carbide turning YT15 contrast. TiC single coated blade wear is much higher than YT15. CVD technology but also has its congenital defects, one process treatment temperature is high, the tool is easy to cause a decline in the flexural strength of the material; the second is the internal film tensile stress state, the use of micro-cracks easily lead; third CVD technology emissions, waste can cause industrial pollution, greater impact on the environment, and the current conflict to promote green industry, so the mid-nineties the development of high-temperature CVD technology subject to certain constraints.




Tungsten Carbide Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-carbide.com.cn
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
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