Tungsten

摘要： In the last decades,technology has used Copper for IC interconnect and it has been the best material used in the wire downsizing.However,Copper is now showing inefficiency as downscaling is getting deeper.Recent research starts to show Tungsten(W)as a possible replacement,for its better downsizing characteristic.The scaling-down of interconnects dimension has to be augmented with thin diffusion layers.It is crucial to subdue tungsten diffusion in the nickel-based thermal spray Flexicord(NiCrAlY)coating layers.Inappropriately,diffusion barriers with thicknesses less than 4.3 nm do not to execute well.With the introduction of two dimensional layers,hexagonal boron has been recommended as a substitute for Tungsten diffusion barrier layers with thicknesses less than 1.5 Nano meters(nm).Nevertheless,vacancies flaws may develop into a Tungsten dissemination path,which is a problematic issue in the manufacturing of diffusion barriers.The energy layer density,of Tungsten atom diffusion via a di-vacancy in NiCrAlY,is computed by density functions 3D.NiCrAlY has complex energy barrier which is thicker than other materials such as Graphene.This is due to the sturdier contact and charge variance of NI and Cr in NiCrAlY.Also,we utilize the energy barriers of several vacancy constructions and produce a dataset to be employed in the proposed 3-imensional deep learning model(3D-DNN).Our trained deep learning neural model can predict the energy barrier of Tungsten diffusion through arbitrarily configured NiCrAlY with accuracy greater than 98.4%in 5×5 cell.Prediction results generate directors on selecting barriers through energy computation.

摘要： This paper focuses on the analysis of properties of tungsten and its alloys,as this is a material employed in the first wall of a fusion reactor.Using different production processes and by adding different impurities to tungsten,new materials can be obtained,with varying physical,chemical and mechanical properties which may help to improve the application to specific situations.In particular,in this work,we investigate the mechanical properties of pure tungsten and tungsten carbide.In both systems,simulated states of metal loading are assessed and collected,using 3D calculation software for metals structures,given the results in terms of deformations.

摘要： We have developed an object kinetic Monte Carlo(OKMC)code and simulated hydrogen-vacancy clustering behavior and dependence on temperature and hydrogen-vacancy ratio in tungsten.For each of the temperatures we simulated from 300 K to1000 K,HnV clusters with smaller n form before those with larger n.The elevating temperature leads to a decrease in hydrogen vacancies:H10V and H9V clusters dominate at 300 K and 600 K,whereas H5V,H6V,and H7V clusters dominate when the temperature reaches 1000 K.Furthermore,only HnV clusters with smaller n formed when a lower hydrogen-vacancy ratio was used due to insufficient availability of hydrogen atoms to occupy vacancies.The results suggest hydrogen emission occurs very rarely at lower temperatures,while higher temperatures facilitate the dissociation of hydrogen from HnV clusters.

摘要： A Chinese company that specializes in tungsten products and rare earths on Monday reported a sharp decline in overall profit,but a surge in profit from its rare-earth business,as the metals essential for high-tech products become a hot commodity amid trade tensions.

摘要： Marinov et al. have detected spontaneous fission events in sources separated from tungsten targets irradiated with 24 GeV protons. These fission events could not be attributed to actinides or to any other known isotope. Marinov et al. propose that fission events are due to production of element 112 (Eka-Hg) in the tungsten target. We have addressed Marinov’s claim with a new analysis of their data and modern theoretical model calculations of possible interactions. Using data available in the literature the spontaneous fission half-life of the Eka-Hg was estimated to be ~74 days. This is dramatically longer than the half-life obtained for 283112Cn, produced in the fusion of energetic 48Ca ions with 238U. Monte Carlo calculations show that enough Sr isotopes are produced in the tungsten target to make the production of element 112 via fusion of Sr and W feasible;however, if such fusion was possible it had to be deep sub-barrier fusion.

摘要： Tungsten carbide films (W-C films) were fabricated on silicon substrates by using the filtered pulse arc deposition (FPAD) method. Two types of cemented tungsten carbide (WC) were used as cathode, one containing Co and the other Ti, which were used as binders for forming the cathode shape. The films were fabricated by varying the pulse arc current and substrate bias voltage. The discharge, deposition and film properties were investigated under these deposition conditions. The cathode wear amount when using WC-Co (WC cathode containing Co) was found to be smaller than that measured when WC-Ti (WC cathode containing Ti) was used. The W-C film thickness was approximately 30 - 40 nm under all conditions, except when the pulse arc current was 50 A and the film thickness, was approximately 10 nm. Compared to the WC-Ti, the consumption of cathode material is suppressed in the WC-Co, indicating that the efficiency for film preparation of the latter is good. From the X-ray diffraction analysis, the crystalline phase of W-C films fabricated using WC-Co and WC-Ti were observed as W2C and WC1-x, respectively, indicating that different crystalline phases could be fabricated using different cathodes. From the X-ray photoelectron spectroscopy analysis, the oxidation layer formed by air exposure was observed to exclusively exist on the W-C film surface. Moreover, almost all oxygen in the oxidation layer bonded with tungsten.

摘要： Visible light-sensitive photocatalyst was developed by combining n-type silicon (n-Si) and tungsten trioxide (WO3, n-Si/WO3), yielding an ohmic contact in between. In this system, the ohmic contact acted as an electron-and-hole mediator for the transfer of electrons and holes in the conduction band (CB) of WO3 and in the valence band (VB) of n-Si, respectively. Utilizing thus- constructed n-Si/WO3, the decomposition of 2-propanolto CO2 via acetone was achieved under visible light irradiation, by the contribution of holes in the VB of WO3 to decompose 2-propanol and the consumption of electrons in the CB of n-Si to reduce O2. The combination of p-type Si (p-Si) and WO3 (p-Si/ WO3), not the ohmic contact but the rectifying contact, was much less effective, compared to n-Si/WO3.

摘要： Listed companies among the six rare earth groups have all released pre-announcement of their first-half annualized report by the end of July, 2016. The weak market imposes heavy strain on these rare earth enterprises. According to the pre-announcement, China Northern Rare Earth predicted 80%-90% net profit decline year-on-year; Rising Nonferrous Metals announced the profit attributable to shareholders would make a loss of 90-110 million yuan; China Minmetals forecasted a loss of 35-45 million yuan; Xiamen Tungsten released 20.73% declined operation revenue.

摘要： A flexible quasi-solid-state electrochromic device (ECD), assembled with a polymeric crystal composite electrolyte and tungsten oxide/nickel oxide (WO3/NiO) complementary system, is demonstrated in this study. The polymer composite, which is composed of a UV-cured ethoxylated trimethylolpropane triacrylate (ETPTA), propylene carbonate (PC) and ferrocene (Fc), is used as the electrolyte in the flexible quasi-solid-state ECD. The optimal composition ration of this composite is at the weight ratio of 15/85 for ETPTA/PC with 1 M LiClO4. For the cathodic electrochromic electrode, a flexible polyethylene terephthalate (PET) is used as the substrate, and indium-tin- oxide (ITO) and WO3 are deposited sequentially on the PET by sputtering. A NiO/ITO/PET electrode prepared by sputtering is used as the anodic coloring electrode. The thickness of ITO, WO3 and NiO film is 110, 70 and 60 nm, respectively. This flexible all-solid-state ECD fabricated with the polymeric crystal composite electrolyte shows an optical contrast of ca. 37.5% at 550 nm. The optical transmittance of the ECD at 550 nm can be reversibly modulated from 47.5% (bleached) to 10.0% (darkened), by applying potentials of 2.5 and 2.5 V, respectively.

摘要： The present study is dealing with the corrosion of copper coated with nanocrystalline nickeltungsten coating. Different plating bath compositions and conditions were used in order to produce nickel-tungsten coatings of different tungsten content 30%, 40% and 50% wt, with a thickness of 20 μm. The corrosion resistance of nickel-tungsten alloy coated copper was examined by a potentiodynamic polarisation technique in NaCl solution (0.03 M, 0.3 M and 1 M) as a function of pH (3, 7, 10) and temperature (7°C, 30°C, 40°C) of the solution. It has been found that the pH value did not seem to affect the corrosion behaviour of the coated specimen remarkably, while the increase of solution temperature increased the corrosion rate of the coated copper specimen. It was finally confirmed that the corrosion products mainly consisted of tungsten and nickel oxides.