Tungsten Dart Billet,Tungsten Dart Price

Ground‐Term Energy Levels of Triply Ionized Holmium in Calcium Tungstate

Details: Category: Tungsten Information; Published on Wednesday, 08 July 2015 15:11; Written by xinyi; Hits: 332

The energy levels of the ⁵I ground term of Ho³⁺ in single crystals of CaWO₄ were established by absorption and fluorescence spectra measurements. The measurements were made using crystals at temperatures near 2, 20, and 85°K. Most of the observed transitions can be accounted for by the electric dipole selection rules. Magnetic dipole selection rules cannot be ruled out for some of the lower energy transitions, however. Calculations were made to determine the effects of the crystalline host material on the Ho³⁺ energy levels. An effective Hamiltonian of the form suggested by Karayianis was diagonalized in a basis of Russell–Saunders wavefunctions to obtain the calculated energy levels and wavefunctions for Ho³⁺. Such a calculation takes into account the complete J mixing of the states within the ground term and is equivalent to determining the effects of the spin–orbit interaction to better than second order. In the calculation, an rms deviation of 10 cm−1 was found as the best agreement between the theoretical and experimental energy levels using the Hamiltonian, H = λ1(L⋅S) + λ2(L⋅S)² + λ3(L⋅S)³ + ΣlmB+lmClm. The empirically determined parameters yielding this rms deviation are (in cm⁻¹): λ₁= − 487.9, λ₂ = − 6.601, λ₃ = − 0.1801, B₂₀ = 436, B₄₀ = − 664, B₄₄ = 779, B₆₀ = − 33,ReB₆₄ = 558, and ImB₆₄ = 196. The g_‖ factor for the ground state of Ho³⁺ in CaWO₄was calculated to be 13.675. This is in agreement to within 0.12% of the experimental value of 13.691 ± 0.006 reported by Kirton.

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 Carbide Powder (2)

Details: Category: Tungsten Information; Published on Wednesday, 08 July 2015 14:51; Written by xiaoshan; Hits: 414

Tungsten carbide powder (WC) is kind of dark gray powder, which using proportional tungsten powder and carbon black mixture as raw material to produce tungsten carbide powder. And in tungsten carbide powder the carbon atoms embedded tungsten metal lattice gap and did not destroy the original metal lattice, but to form interstitial solid solution, also known as interstitial compound. It is mainly used in produce tungsten carbide alloy.
The production of tungsten carbide powder is mainly through mix metal tungsten powder and carbon black as raw materials which according to a certain proportion of formulated. And then putting mixture into the graphite boat and placed in the carbon tube furnace or a sense of high-frequency electric furnace with a certain temperature to carbonization, and then by ball milling, screening to obtain tungsten carbide powder.
Tungsten carbide powder should be stored in dry, ventilation and acid-free atmosphere, to prevent oxidation, in which the storage period should not exceed six months. The external package of tungsten carbide should be drum and the internal packaging should be polyethylene bags, tightly sealed. According to fsss's size, tungsten carbide powder can be divided into 12 grades, as shown below.

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’s Application

Details: Category: Tungsten Information; Published on Wednesday, 08 July 2015 14:46; Written by xiaoshan; Hits: 454

Tungsten hexafluoride (WF6) is only stable varieties in tungsten fluoride which can produce by industrial. It is mainly used in the chemical vapor deposition of tungsten, the chemical equation for this reaction is: WF6 + 3H2 → W + 6HF. The reduction of tungsten hexafluoride can be restore to metallic tungsten and HF by hydrogen or other reducing gas (such as GeH4, SiH2F2 and diethylsilane etc.) at high temperatures. Tungsten hexafluoride as a raw material widely used in the electronics industry as base of tungsten metal chemical vapor deposition (CVD) process technology, such as using WSi2 as wiring materials of LSI which is made by WF6. Besides, using CVD technology of mixing metal to produce tungsten and the rhenium complex coating may be used to manufacture X-rays emitter electrode of a solar absorber. What’s more WF6 in the electronics industry still mainly used as a semiconductor electrode and the conductive paste and other raw materials.
In addition to applications in the electronics industry, tungsten hexafluoride used in non-electronic aspect is also very broad. By CVD technology to generate hard tungsten carbide on the surface of the steel can improve the surface properties of the steel. Additionally, tungsten hexafluoride is also widely used in fluorinating agent, polymerization catalyst and feedstock of optical materials to manufacture low resistance and high melting point interconnect lines or some components, such as tungsten tube and crucibles.

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 Carbide Powder (1)

Details: Category: Tungsten Information; Published on Wednesday, 08 July 2015 14:48; Written by xiaoshan; Hits: 383

Tungsten carbide powder (WC) as a black hexagonal crystal with a metallic luster, a dark gray powder, the hardness close to diamond, is the main raw material for the produce tungsten carbide. Its physical characteristics are as follows: chemical formula: WC, melting point: 2870 ℃, boiling point: 6000 ℃, the relative density of 15.63 (18 ℃), it does not dissolve in water, hydrochloric acid and sulfuric acid, easily dissolved in mixture acid of nitric acid and hydrofluoric acid which is a good conductor of electricity and heat. Tungsten carbide is fragile, if adding a small amount of infiltration of titanium such as cobalt, titanium and other metals can reduce brittleness, but also make the tungsten carbide used in more areas. Using tungsten carbide as steel cutting tools used often adding titanium carbide, tantalum or they mixtures in order to improve the anti-knock capacity.
Tungsten carbide powder may be dissolved in a variety of carbide, especially in titanium carbide forming solid solution TIC-WV. Another compound of tungsten and carbon is tungsten dioxide carbide, the formula W2C, a melting point of 2860 ℃, boiling point of 6000 ℃, the relative density of 17.15, while its properties, preparation method, use of tungsten carbide powder and similar.

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 Synthesis (3)

Details: Category: Tungsten Information; Published on Wednesday, 08 July 2015 14:41; Written by xiaoshan; Hits: 325

There are many synthetic methods tungsten hexafluoride. The following introduce chemical reactions which use tungsten, halogen and HF to react then to form tungsten hexafluoride. Tungsten hexafluoride formed by the react of tungsten, halogen and HF where the chemical reaction equation is as follows: W + 3X2 + 6HF - WF6 + 6HX. Wherein the X2 is a halogen, usually Cl2 or Br2, the reaction is carried out in an autoclave which make by monel alloy.
Using Cl2 as example, in order to ensure that the product has a good yield, generally make Cl2 and HF appropriate excess, in the theory chlorine and tungsten hexafluoride molar ratio of 3: 1, while in the experiment used 3~6: 1. Theory hydrogen fluoride and tungsten hexafluoride molar ratio of 6: 1, is used in the experiment used 6~10: 1, the reaction temperature is controlled at 150 ~ 450 ℃. While increasing the reaction temperature can make the reaction quickly but the temperature is too high will cause severe corrosion of equipment and WF6 partially decomposed.
By the way this method often has by-product, it is not a good way for produce tungsten hexafluoride not only by environmental protection or economic efficiency.

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