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1
Content available remote Magnes Bittera wykonany z wolframu i chłodzony ciekłym helem
PL
Opisano projekt magnesu Bittera wykonanego z płyt wolframowych i chłodzonego ciekłym helem o temperaturze 4,2 K. Obliczono indukcję pola magnetycznego wytwarzanego przez ten magnes, jego moc zasilania i parametry układu chłodzenia. Moc ta jest ok. 104 razy mniejsza, niż moc zasilania powszechnie używanych magnesów Bittera wykonanych z miedzi i chłodzone wodą. Wykazano wykonalność tego magnesu przy użyciu dostępnych obecnie możliwości technicznych.
EN
The project of the Bitter magnet made of tungsten plates and coiled by liquid helium in temperature of 4 K is described. The magnetic flux density produced by this magnet, power supply and coiling system parameters are calculated. This power is about 104 times smaller than power of commonly used Bitter’s magnets made of cooper and coiled by water. Feasibility of this magnet by using of the present accessible technical aids is demonstrated.
2
Content available The Proposal of Tungsten Ores Processing in Rwanda
EN
Tungsten is one of the rare elements occurring in Earth. Its applicability and request for it causes that the production of this metal is very beneficial. One of the biggest deposits of this metal ores in the world is located in African country of Rwanda. Due to the lack of appropriate technology and lack of investments the current way of producing this valuable metal in this country causes that much of tungsten is wasted as well the production is slow and the results are not appropriate. That is why an attempt to propose an adequate processing way for this deposit was done and is presented in this paper. Authors performed several tests on the ore originating from Rwanda, including its mineralogical composition and tests performed by means of laboratory shaking table. The results are promising and the further tests, including other methods of beneficiation are planned, like second shaking table stage and flotation.
PL
Wolfram jest jednym z pierwiastków rzadkich występujących na Ziemi. Jego zastosowania oraz zapotrzebowanie świata na ten produkt powodują, że produkcja tego metalu jest bardzo opłacalna. Jedno z największych złóż rudy tego metalu na świecie jest zlokalizowane w afrykańskim państwie, jakim jest Rwanda. Ze względu na brak odpowiedniej technologii oraz brak inwestycji obecny sposób produkcji tego cennego metalu w tym państwie powoduje, że duża ilość wolframu jest tracona, produkcja jest powolna, a wyniki nie są satysfakcjonujące. Dlatego przeprowadzono próbę zaproponowania odpowiedniego sposobu przeróbki tego złoża, która została zaprezentowana w tym artykule. Autorzy wykonali dużo ilość testów przeprowadzonych na rudzie sprowadzonej z Rwandy, włączając w to jej skład mineralogiczny, jak również testy laboratoryjne wzbogacania na stole koncentracyjnym. Wyniki są obiecujące a dalsze testy, włączając w to także inne metody wzbogacania są planowane do przeprowadzenia, biorąc pod uwagę drugi etap wzbogacania na stole koncentracyjnym czy flotację.
EN
The paper takes into account mineral commodities that have been listed as critical by the EU Commission. It concentrates attention on the issue of global demand/supply balances, and summarizes causes for critical listing of these commodities.
PL
W artykule przedstawiono surowce mineralne wymienione przez Komisję Europejską jako krytyczne. Koncentruje uwagę na globalnym popycie i podsumowuje przyczyny zestawienia listy pierwiastków krytycznych.
EN
The mining waste and tailing dam are object of discussion due to the accidents that occur due to a lack of control or due to interest in the remaining minerals present in these materials. Most of the old tailings dams have high contents of heavy metals which could represent potential risks to the environment or be an alternative source of some critical raw materials. The case study of the Cabeco do Piao dam in Central Portugal involved tailings from a processing plant that belonged to the Panasqueira Mine Complex, which has been in operation for over 120 years. Waste rock and mining tailings were deposited in the area until 1995, and they represent an environmental liability for the local population due to their high content of toxic metals. Tailings reprocessing can be considered as a solution that minimizes social and environmental impacts, recovers some essential minerals, such as Zn, W, and Cu which can help to offset investments made. The project design involves several stages of metal concentration, determined by experiments, as well as a model of the process. The overall model will take into account technological constraints, social-economic conditions and environmental impacts. A preliminary result of an optimization study of the kinetic approach is presented in this piece of work.
EN
The paper has focused on market for critical raw materials and its influence on mineral prices. Usually ores and ore products are deemed critical raw materials if they mostly or totally come from foreign countries, have difficult replacement, and are vital for the Nation’s economy, especially for defence issues. Tungsten, niobium, graphite and lithium were chosen for analysis from the critical mineral commodities declared by the European Commission and the Government of the Czech Republic. An analysis of these mineral commodity market conditions has been made, and their impacts on particular mineral availability and price have been assessed. As regards tungsten supplies, there are relatively many producer countries with the existing or developing extraction structures, but China has at its disposal 60% of the deposits. Lithium reserves are sufficient, but supplies are highly concentrated – four producer companies deliver about 90% of lithium in the world. Also niobium supplies are extremely concentrated, in the period, 2009–2012, two Brazilian mines and a single Canadian one produced 99% of niobium in the world. The biggest world producer of natural graphite is China that dominates 70% of the market. Natural resources of the above mentioned mineral commodities are not critical. The Earth’s crust deposits are sufficient for long-term exploitation, and what’s more, a technology has been patented for lithium recycling. What rather matters is the issue of the free play of market forces. The theoretical preconditions for the free play of market forces and balanced price convergence – market presence of many various producers and many customers – are disturbed by producer structure, high concentration of mining companies and countries. Free market interference is implied in dominance of individual producer countries or production companies, and their ability to decide about production levels and related prices. Nevertheless, the inevitable rise of mineral commodity prices will mean that exploitation of some sources, which are currently deemed uneconomical, may become interesting.
PL
W artykule skoncentrowano się na rynku surowców krytycznych i ich wpływie na ceny surowców mineralnych. Zazwyczaj rudy i produkty wzbogacania uznane za surowce krytyczne surowce jeśli w większości lub w całości pochodzą z innych krajów, mają trudno zastępowalne i są niezbędne w gospodarce narodowej, zwłaszcza dla przemysłu obronnego. Jako przedmiot analizy wybrano wolfram, niob, grafit i lit będące surowcami krytycznymi w dokumentach opublikowanych przez Komisję Europejską i rząd Republiki Czeskiej. Przeprowadzono analizę rynku surowców oraz jego wpływ na dostępność i cenę minerałów. Zasobywolframu zostały zidentyfikowane w kilku krajach natomiast 60% złóż znajduje się w Chinach. Rezerwy litu są wystarczające, ale podaż jest bardzo skoncentrowana cztery firmy producenckie dostarczają około 90% litu. Również podaż niobu jest niezwykle skoncentrowana, w latach 2009-2012 dwie kopalnie brazylijskie i jedna kanadyjska wyprodukowały 99% niobu na świecie. Największym światowym producentem grafitu naturalnego są Chiny, które obejmują 70% rynku światowego. Zasoby naturalne wymienionych surowców mineralnych nie są krytyczne. Złoża skorupy ziemskiej są wystarczające dla długotrwałej eksploatacji, a ponadto opatentowano technologie recyklingu np. litu. Isotny jest problem gry wolnorynkowej. Teoretyczne warunki wstępne dla swobodnej gry sił rynkowych i zrównoważonej konwergencji cen – rynek to obecność wielu różnych producentów i wielu klientów – warunki są zakłócane przez strukturę producentów, dużą koncentrację firm górniczych. Zakłócenia wolnego rynku są implikowane przez dominację poszczególnych krajów producenckich lub przedsiębiorstw produkcyjnych, oraz ich zdolność do decydowania o poziomach produkcji i cenach. Niemniej jednak nieunikniony wzrost cen surowców mineralnych może oznaczać, że wykorzystanie niektórych źródeł, które obecnie uważa się za nieekonomiczne, może stać się interesujące.
PL
To miał być artykuł na koniec wakacji, ale może dobrze się stało, że napisałem wtedy nieco bardziej rozrywkowy tekst o podróżowaniu. Ten poniżej zmusza do chwili refleksji i wpisuje się w szeroko dyskutowany problem wzrostu zapotrzebowania i spadku wystarczalności surowców mineralnych, a także pogoni za nimi.
EN
WO3 modified TiO2 nanotube array (WO3/TNAs) photoelectrodes were fabricated via electrochemical deposition on TNAs/Ti photoelectrodes. The morphology and structure of WO3/TNAs photoelectrodes were investigated by scanning electron microscopy (SEM) and X-ray diffractometer (XRD). The effects of deposition potential, deposition duration, NaWO4 concentration, and calcination temperature on the morphology and the photocatalytic activity were investigated. The results showed that suitable amounts of WO3 promoted the photocatalytic activity of TNAs photoelectrodes for the degradation of dimethyl phthalate (DMP). The optimal conditions for the fabrication of WO3/TNAs photoelectrodes were as follows: deposition voltage 3.0 V, 10 min deposition duration, 0.01 mol/dm3 Na2WO4 concentration, 1.5 cm electrode gap, and 550 °C annealing temperature. The degradation rate of DMP reached 77% after 60 min of illumination by WO3/TNAs photoelectrode. Additionally, WO3/TNA photoelectrodes possessed superb stability for maintaining a high DMP degradation efficiency at more than 75% after 10 times of successive use with 60 min irradiation for each cycle. The enhancement of photocatalytic performance by the efficient combination of WO3 with TNAs would provide a theoretical basis for the practical application of WO3/TNA photoelectrodes in water treatment.
PL
W artykule przedstawiono główne właściwości i zastosowania wolframu oraz metody recyklingu odpadów wolframowych, ze szczególnym uwzględnieniem odpadów zawierających węgliki spiekane. Obszernie omówiono znane zarówno z praktyki przemysłowej jak i z licznych doniesień literaturowych i patentów, procesy odzysku wolframu jak i kobaltu - metalu będącego spoiwem węglików. Scharakteryzowano wszystkie metody wskazując ich zalety i wady oraz możliwości zastosowania ich do kompleksowej technologii odzysku wolframu i kobaltu w postaci związków wysokiej czystości.
EN
The article presents main properties and applications of tungsten and the recovery methods of tungsten wastes with special consideration of wastes containing sintered carbides. Known tungsten and cobalt (which is used as carbides binder) recovery processes, both from industrial practice and numerous literature reports and patents, were extensively discussed in this paper. These methods were characterized, showing their advantages and disadvantages, and their application possibility for tungsten and cobalt comprehensive recovery technology in a form of high purity compounds.
9
Content available remote Laser alloying of Vanadis-6 steel by using powders containing boron and tungsten
EN
The paper presents the influence of laser alloying on microstructure and microhardness of Vanadis-6 steel. The surface layers were formed by remelting paste which was applied on to the steel substrate. Three kind of pastes were applied: with boron, with tungsten and the mixture of these elements in the ratio 1:1. TRUDIODE 3006 diode laser with nominal power equal to 3 kW integrated with robot arm were used. Parameters of laser alloying were following: power density of laser beam q = 63.69 kW/cm2, scanning rate v = 3.0 m/min and overlap of laser tracks equal to 60%. Microstructure of produced laser tracks were analysed. Surface roughness after laser alloying were investigated. After laser alloying, microstructure consisting with remelted zone and martensitic heat affected zone were obtained. Application of paste with tungsten had contributed to formation the solid solution microstructure, while application of paste with boron or mixture (boron and tungsten) led to formation of boron–martensite eutectic microstructure. Microhardness of laser tracks were measured. It was found that paste containing boron and tungsten allows obtain the layers with increased microhardness compared to steel substrate while maintaining the mild microhardness profile from surface to the substrate.
PL
W pracy przedstawiono wyniki badań wpływu laserowego stopowania wybranymi proszkami na mikrostrukturę, mikrotwardość i chropowatość powierzchni stali Vanadis-6. Warstwy powierzchniowe wytworzono przez przetopienie past naniesionych na podłoże stalowe, zawierających bor, wolfram oraz mieszaninę tych pierwiastków w proporcji 1:1. Celem pracy było określenie wpływu poszczególnych pierwiastków na wybrane właściwości.
EN
The influence of extreme heat loads, as produced by a multiple pulses of non-homogeneous flow of slow plasma (0.1–1 keV) and fast ions (100 keV), on double-forged tungsten (DFW) was investigated. For generation of deuterium plasma and fast deuterons, plasma-focus devices PF-12 and PF-1000 are used. Depending on devices and conditions, the power flux density of plasma varied in a range of 107–1010 W/cm2 with pulse duration of 50–100 ns. Power flux density of fast ions was 1010–1012 W/cm2 at the pulse duration of 10–50 ns. To achieve the combined effect of different kind of plasmas, the samples were later irradiated with hydrogen plasma (105 W/cm2, 0.25 ms) by a QSPA Kh-50 plasma generator. Surface modification was analysed by scanning electron microscopy (SEM) and microroughness measurements. For estimation of damages in the bulk of material, an electrical conductivity method was used. Investigations showed that irradiation of DFW with multiple plasma pulses generated a mesh of micro- and macrocracks due to high heat load. A comparison with single forged tungsten (W) and tungsten doped with 1% lanthanum-oxide (WL10) reveals the better crack-resistance of DFW. Also, sizes of cells formed between the cracks on the DFW’s surface were larger than in cases of W or WL10. Measurements of electrical conductivity indicated a layer of decreased conductivity, which reached up to 500 µm. It depended mainly on values of power flux density of fast ions, but not on the number of pulses. Thus, it may be concluded that bulk defects (weakening bonds between grains and crystals, dislocations, point-defects) were generated due to mechanical shock wave, which was generated by the fast ions flux. Damages and erosion of materials under different combined radiation conditions have also been discussed.
EN
This paper presents results of experimental studies of tungsten samples of 99.95% purity, which were irradiated by intense plasma-ion streams. The behaviour of tungsten, and particularly its structural change induced by high plasma loads, is of great importance for fusion technology. The reported measurements were performed within a modifi ed PF-1000U plasma-focus facility operated at the IFPiLM in Warsaw, Poland. The working gas was pure deuterium. In order to determine the main plasma parameters and to study the behaviour of impurities at different instants of the plasma discharge, the optical emission spectroscopy was used. The dependence of plasma parameters on the initial charging voltage (16, 19 and 21 kV) was studied. Detailed optical measurements were performed during interactions of a plasma stream with the tungsten samples placed at the z-axis of the facility, at a distance of 6 cm from the electrode outlets. The recorded spectra showed distinct WI and WII spectral lines. Investigation of a target surface morphology, after its irradiation by intense plasma streams, was performed by means of an optical microscope. The observations revealed that some amounts of the electrodes material (mainly copper) were deposited upon the irradiated sample surface. In all the cases, melted zones were observed upon the irradiated target surface, and in experiments performed at the highest charging voltage there were formed some cracks.
EN
Ceramic - metal composites are widely used materials in a whole world. There were invented many fabrication methods for those kind of materials, but still exists some problems which need to be fixed. Stability of high density metal particles (e.g. W, Mo, Nb) in ceramic-metal composite suspensions is one of crucial issues to be solved in order to obtain homogenous composite material with desired properties such as high fracture toughness, mechanical strength, hardness, wear resistance. In this paper, results of two different methods of stabilizing W particles in Al2O3 - W - H2O system were compared. The zeta potential by laser doppler electrophoresis, stability by static multiple light scattering and rheological behavior of prepared suspensions were analyzed. As a result application of hetero-flocculation effect was consider as a good way to obtain homogeneous dispersion of metal particles with a high density.
PL
W artykule przedstawiono sposób odzysku wolframu i kobaltu z odpadów pochodzących z obróbki węglików spiekanych. Zaproponowana metoda polega na ługowaniu odpadów roztworami H2SO4 lub HCl, z dodatkiem czynnika utleniającego, dla przeprowadzenia do roztworu kobaltu i innych metali, z równoczesnym pozostawieniem całości wolframu w szlamie powstającym po ługowaniu. Prażenie tego szlamu po ługowaniu, w temperaturze 550-600 °C, z dostępem powietrza, powoduje zniszczenie struktury spieków, wypalenie węgla i wytworzenie tlenków wolframu, surowca do otrzymywania handlowych związków wolframu, np. H2WO4. Z roztworów uzyskanych po ługowaniu wydziela się bezpośrednio, przez zatężanie, uwodnione sole kobaltu, tj.: CoSO4 lub CoCl2. Aby otrzymać związki kobaltu wysokiej czystości, stosuje się metodę wymiany jonowej. Selektywne rozdzielenie kobaltu od pozostałych składników roztworu przez sorpcję z zastosowaniem odpowiednio dobranych żywic i elucję roztworami kwasów (HCl lub H2SO4) umożliwia uzyskanie czystych, roztworów o zawartości kobaltu wynoszącej kilkanaście gramów w litrze i krystalizację soli o wysokiej czystości.
EN
The paper presents a method of tungsten and cobalt recovery from sintered carbides treatment wastes. Initially the wastes are dissolved with a H2SO4 or HCl with addition of oxidising reagent. The cobalt and other metals except for the tungsten are transferred to the solution. The residue is roasted at temperature range from 550 to 600 °C in the presence of air. During the process structure of the sinter is destroyed with simultaneous combustion of the total carbon present. Tungsten oxides are formed during that process, which can be further processed to obtain commercial tungsten compounds, for example H2WO4. The cobalt salts (CoSO4 or CoCl2) can be obtained from the solutions by evaporation. Alternatively cobalt compounds of high purity can be produced using ion exchange technique. Cobalt is selectively separated from the other solution components using a dedicated ionite and consecutive elution with acid solutions (HCl or H2SO4). Obtained highly concentrated solutions with cobalt content up to 20 g/dm3 are used for crystallization of high purity salts.
14
Content available remote Plasma spheroidisation of high melt point materials on example of tungsten
EN
Particle shape and size, density and distribution are important characteristics of the powders processed by additive manufacturing processes e.g. Selective Laser Melting (SLM) or Electron Beam Melting (EBM). Spherical shape of powder particles allows to stably carrying out the process and affects also the manufactured objects properties. Desired morphology of the powder can be achieved by powder manufacturing process or by additional treatment of the non-spherical powders. This paper is dedicated to study spheroidization of tungsten powder by Atmosphere Plasma Spraying (APS). Influence of APS process parameters and preliminary powder treatment has been analysed. Scanning electron microscopy (SEM) was used for the evaluation of shape, size and distribution of post-processed powder particles.
PL
Kształt oraz wielkość cząstek, gęstość oraz rozkład są istotnymi cechami charakterystycznymi proszków przetwarzanych za pomocą technologii przyrostowych n.p. selektywnej laserowej mikrometalurgii proszków (SLM) lub elektronowej mikrometalurgii proszków (EBM). Sferyczny kształt cząstek proszku umożliwia stabilne prowadzanie w/w procesów oraz wpływa na własności wytwarzanych nimi obiektów. Oczekiwana morfologia proszku może być osiągnięta za pomocą jego procesu wytwarzania, jak również poprzez dodatkową obróbkę proszków niesferycznych. Artykuł jest poświęcony badaniom sferoidyzacji proszku wolframu za pomocą natryskiwania plazmowego (APS). Został przeanalizowany wpływ parametrów procesu oraz wstępnej obróbki proszku. Do oceny kształtu, wielkości i dystrybucji otrzymywanych cząstek proszku została zastosowana skaningowa mikroskopia elektronowa (SEM).
PL
W artykule przedstawiono wyniki badań procesu wytwarzania i właściwości wolframowego spieku ciężkiego, przeznaczonego na rdzenie podkalibrowych pocisków przeciwpancernych. Badany materiał zawierał 77% wolframu, 20% renu oraz 3% niklu. Próbki do badań wykonywano technologią metalurgii proszków. Zastosowano izostatyczne prasowanie mieszanki proszków i dwustopniowe spiekanie: wstępne - w atmosferze zdysocjowanego amoniaku i ostateczne - w próżni. W artykule zamieszczono schemat wytwarzania tego spieku i pokazano przykładowe obrazy jego mikrostruktury. W dalszej części zamieszczono wyniki analizy składu chemicznego w wybranych mikroobszarach badanego materiału oraz wybrane właściwości mechaniczne, takie jak wytrzymałość na ściskanie i twardość. Z otrzymanych spieków wykonano rdzenie do pocisków i umieszczano je w stalowym sabocie. Pokazano wyniki eksperymentów balistycznych dotyczących badania właściwości penetracyjnych w zakresie zastosowania tego spieku na rdzenie pocisków przeciwpancernych. Określono współczynnik penetracji, a także przedstawiono obrazy przekrojów rdzeni po strzelaniu. W oparciu o zdjęcia wykonane przy zastosowaniu skaningowego mikroskopu elektronowego opisano mikrostrukturę wybranych próbek. Ustalono, że procesowi penetracji towarzyszyło zjawisko samoostrzenia rdzenia.
EN
The results of investigation of production process and properties of W-Re-Ni sinters intended for cores of anti-tank missiles were presented in the paper. The tested material contained 77% of tungsten, 20% of rhenium and 3% of nickel. The test specimens were made by powder metallurgy. The production process consisted of powder mixture pressing by CIP method and two-stage sintering: initial - in an atmosphere of dissociated ammonia and final - in vacuum. The diagram of the production process of this sinter and exemplary picture of its microstructure were shown in the paper. The results of the analysis of the chemical composition of selected microregions examined materials, and selected mechanical properties such as compressive strength and hardness were presented in the next part of the paper. The cores of the projectiles, which were made from the examined materials, were put in a steel sabot. The results of experiments connected with investigation of the penetration properties in the field of using this sinter as the cores of anti-tank shells were shown. The penetration coefficient was determined, and moreover cross-sectional images of the cores after shooting were presented. Based on the photographs taken using a scanning electron microscope the microstructure of selected samples was described. It was settled that the cores selfsharpening phenomenon was appeared during penetration.
PL
W pracy przedstawiono wpływ wolframu na proces krystalizacji, mikrostrukturę i właściwości mechaniczne siluminu 226 w warunkach zbliżonych do równowagowych oraz odlewanych ciśnieniowo. Wykazano wzrost właściwości zarówno wytrzymałościowych, jak i plastycznych odlewów z siluminu z dodatkiem około 0,3−0,4% wag. W odlewanych ciśnieniowo.
EN
The effect of tungsten on the solidification process, microstructure and mechanical properties of silumin 226 under the conditions close to equilibrium during pressure die casting was discussed. An increase in both mechanical and plastic properties of the pressure die cast silumin with 0.3−0.4 wt. % W was demonstrated.
EN
In this note experimental studies of tungsten (W) samples irradiated by intense plasma-ion streams are reported. Measurements were performed using the modified plasma focus device DPF-1000U equipped with an axial gas-puffing system. The main diagnostic tool was a Mechelle®900 optical spectrometer. The electron density of a freely propagating plasma stream (i.e., the plasma stream observed without any target inside the vacuum chamber) was estimated on the basis of the half-width of the Dβ spectral line, taking into account the linear Stark effect. For a freely propagating plasma stream the maximum electron density amounted to about 1.3 × 1017 cm–3 and was reached during the maximum plasma compression. The plasma electron density depends on the initial conditions of the experiments. It was thus important to determine first the plasma flow characteristics before attempting any target irradiation. These data were needed for comparison with plasma characteristics after an irradiation of the investigated target. In fact, spectroscopic measurements performed during interactions of plasma streams with the investigated W samples showed many WI and WII spectral lines. The surface erosion was determined from mass losses of the irradiated samples. Changes on the surfaces of the irradiated samples were also investigated with an optical microscope and some sputtering and melting zones were observed.
EN
Tungsten is a prime candidate material for the plasma-facing components in future fusion devices, e.g. ITER and DEMO. Because of the harsh and complex loading conditions and the differences in material properties, joining of the tungsten armor to the underlying construction and/or cooling parts is a complicated issue. To alleviate the thermal stresses at the joint, a sharp interface may be replaced by a gradual one with a smoothly varying composition. In this paper, several techniques for the formation of tungsten-steel composites and graded layers are reviewed. These include plasma spraying, laser cladding, hot pressing and spark plasma sintering. Structure, composition and selected thermal and mechanical properties of representative layers produced by each of these techniques are presented. A summary of advantages and disadvantages of the techniques and an assessment of their suitability for the production of plasma-facing components is provided.
EN
Tungsten is a prime choice for armor material in future nuclear fusion devices. For the realization of fusion, it is necessary to address issues related to the plasma–armor interactions. In this work, several types of tungsten material were studied, i.e. tungsten prepared by spark plasma sintering (SPS) and by water stabilized plasma spraying (WSP) technique. An intended surface porosity was created in the samples to model hydrogen/ helium bubbles. The samples were subjected to a laser heat loading and a radiation loading of deuterium plasma to simulate edge plasma conditions of a nuclear fusion device (power density of 108 W/cm2 and 107 W/cm2, respectively, in the pulse intervals up to 200 ns). Thermally induced changes in the morphology and the damage to the studied surfaces are described. Possible consequences for the fusion device operation are pointed out.
EN
Aluminized melt-cast TNT and PBX (cast/pressed) based compositions have been widely studied and used in different warheads for various applications,such as air blast, underwater blast, thermobaric effects, etc. Tungsten (W) based cast PBX formulations are the least reported in the literature. We have partially replaced RDX or HMX in the control PBX formulation with 15 to 25% W powder and investigated the effect of this on the ease of processing, density, sensitivity, mechanical properties and explosive performance. The viscosity was improved from 9 to 3 kPoise, and the density by about 12 to 25% on the addition of W powder to the PBX formulations. The sensitivity to impact for the RDX/Wand HMX/W based PBX formulations was improved by 12 to 37%. The reinforcing effect of the W powder caused an increase in hardness (Shore A) by 16 to 45%. A decreasing trend in the velocity of detonation (VOD) was observed because of the replacement of the nitramine content (RDX/HMX) with W powder. The approximate detonation pressure of RDX/W/HTPB (65/20/15), roughly calculated by the Kamlet-Jacobs method, is better than the other tungsten based formulations investigated.
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