rhenium containing structure
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- rhenium containing structure
In this case, the heteropolyacid structure is to be hydrolyzed under alkaline conditions and produced molybdate anions are repulsed from the cation exchange, i.e., negatively charged matrix. ... Blokhin, A. et al. (2009), "Ion Exchange Recovery of Rhenium from Molybdenum Containing Sulfuric Acid Solutions," Russian Journal Non-ferrous ...
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In the sodium aluminophosphate glasses, Re is present in both metallic Re(0) form and Re(VII). In the Sodium aluminum-iron phosphate glasses, regardless of the conditions of their production, all the Re occurred as Re(VII). Elemental leach rates from the Re-containing glasses were found to be lower than the standard values.
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The sample containing Re is sintered at 600-700 °C for 2-3 h with CaO and Ca (NO 3) 2, then the sinter is leached with hot dilute bromine water. Most metals (including …
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and structure of the coating were studied by variety of . ... rhenium-containing nickel superalloy in sulfuric acid . electrolytes, Russian Metallurgy 2011 (6) 589-593 (in . Russian).
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The chemical and phase compositions of a rhenium-ruthenium-containing fifth-generation VZhM8 nickel superalloy, which is intended for single-crystal turbine blades of an aviation engine, are calculated using computer simulation. VZhM8 alloy <001>, <011>, and <111> single crystals are fabricated. The microstructure, the γ/γ' misfit, the …
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The nature of stability of dendritic microsegregation of rhenium in single crystals of intermetallic (γ′ + γ) alloys based on γ′-Ni 3 Al is determined under a high-temperature heat treatment and under creep and endurance tests. It is assumed that steady dendritic microsegregation of rhenium is a factor determining the high high-temperature …
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Abstract. A novel fluorine-18 method employing rhenium(I) mediation is described herein.The method was found to afford moderate to high radiochemical yields of labelled rhenium(I) complexes.Subsequent thermal dissociation of the complexes enabled the radiosynthesis of fluorine-18 labelled pyridine bidentate structures which could not be …
به خواندن ادامه دهیدRhenium – the hot superalloy element. The jet turbines in newer generation U.S. fighters, such as these F35s flying over Alaska, are made from nickel-based alloy containing 6 percent rhenium. With a melting point of 5,756 degrees Fahrenheit and a heat-stable crystalline structure, rhenium is extremely resistant to both heat and wear.
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The rhenium clusters are only a handful of atoms large and are a common occurrence in rhenium-containing alloys . Fuchs suggested that TCPs could occur during the solution process under certain circumstances [ 7 ], particularly if the solution process was shortened as it would lead to reduced homogenization.
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Two fac-Re(CO)3-based rectangles containing the dithienylethene-based 4,4′-bipyridyl ligand display photochromic properties both in solution and in the single-crystal state. Photochromic Rhenium-Based Molecular Rectangles: Syntheses, Structures, Photophysical Properties, and Electrochemistry | Inorganic Chemistry
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Rhenium is one of the rarest elements in Earth's continental crust; its estimated average crustal abundance is less than 1 part per billion. Rhenium is a metal that has an extremely high melting point and a heat-stable crystalline structure. More than 80 percent of the rhenium consumed in the world is used in high-temperature superalloys, …
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Before early 80′s, spent rhenium-containing catalysts were primarily treated by caustic dissolution. But it is difficult to recover rhenium from caustic solutions and residues. Thus, sulfuric acid dissolution has become the most favorable processing route today to treat spent rhenium-containing catalysts. A typical flowsheet is shown in Fig. 8.
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absorption and fine structure (EXAFS) measurements have also been car- ried out on the supported rhenium oxide on alumina system by Ellison et al. [19]. The measurements were made under ambient conditions on the Re Ls edge for rhenium oxide on alumina catalysts prepared from ammonium perrhenate.
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A crystal structure containing Rhenium: Image showing CSD Entry: ACAHAN, Rhenium atoms shown as blue spheres. Facts about this structure: Formula: (C70 H56 Mn4 N14 …
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Rhenium is one of the rarest elements in Earth's continental crust; its estimated average crustal abundance is less than 1 part per billion. Rhenium is a metal that has an …
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1. Introduction. Rhenium has the characteristics of high melting point, good interface stability and cohesiveness [1], [2], [3], and can form alloys with most metals over a wide range of concentrations [4].In recent years, related works have studied the high temperature applications of various rhenium alloys, Xu [5], Dong [6] and Fu [7] et al. …
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Abstract Comparative long-term creep tests of [001] single crystals of third-generation rhenium-containing nickel-based superalloy VZhM1 and fourth generation rhenium- and ruthenium-containing nickel-based superalloy VZhM4 were performed at temperatures of 850, 1000, 1100, and 1150°C for durations up to ~3000 h. It has been …
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equilibrium structure of rhenium-containing alloys, was modified . to give the version known as 'Super 5' [16]. The compositions of . the TCP phases for the ahoy RR2071 predicted using this .
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The β− emitter, rhenium-188 (188Re), has long been recognized as an attractive candidate for targeted cancer radionuclide therapy (TRNT). This transition metal shares chemical similarities with its …
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A possible crystal structure of Rhenium is hexagonal close-packed structure. In metals, and in many other solids, the atoms are arranged in regular arrays …
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Single crystals of rhenium-containing ZhS32-VI, ZhS32U nickel superalloys with the 〈001〉, 〈011〉, and 〈111〉 crystallographic orientations have been produced by directional solidification. The alloying element segregations and the thermal stability of the microstructure consisting of a γ solid solution and hardened by precipitates of the γ′ …
به خواندن ادامه دهیدFigure 8. Optica! micrographs oj (a) a eVD WoRe aUoy containing <5% Re, showing a columnar microstructure; (b) a eVD WoRe aUoy containing 10-20% Ae, wilh a !ess-oriented microstructure; and (cl a eVD WoRe aUoy containing 25-30% Re, showing a laminar microstrLlClure. duced is the columnar, highly oriented structure shown in FigureS. …
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Rhenium (Re), chemical element, a very rare metal of Group 7 (VIIb) of the periodic table and one of the densest elements. Predicted by the …
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The chemical and phase compositions of a rhenium-ruthenium-containing fifth-generation VZhM8 nickel superalloy, which is intended for single-crystal turbine blades of an aviation engine, are ...
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Additively manufactured tungsten-rhenium alloys have been compared with pure tungsten in terms of their volumetric density, cracking behavior, microstructure, and hardness. The compositions W-5 wt.%Re and W-25 wt.%Re were explored. Increasing the rhenium content led to an increasing percentage of the theoretical density, with a …
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Highlights. Rhenium coating was prepared on the isotropic graphite and C/C composite by chemical vapor deposition. The rhenium coating on the isotropic graphite was compact and crack-free with a preferential growth orientation of 〈0 0 2〉. The cracks in the coating on C/C composite were resulted from thermal expansion mismatch and …
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Synthesis, structure and reactivity of tetranuclear square-type complexes of rhenium and manganese bearing pyrimidine-2-thiolate (pymS) ligands: versatile and efficient precursors for mono- and polynuclear compounds containing M(CO)3 (M = Re, Mn) fragments. Dalton Transactions 2009, 100 (23), 4458.
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A team approach has been used to develop a family of two nickel-base single crystal alloys (CMSX-4 ® containing 3% Re and CMSX ® −10 containing 6% Re) and a directionally solidified, columnar grain nickel-base alloy (CM 186 LC ® containing 3% Re) for a variety of turbine engine applications. A range of critical properties of these …
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Element Rhenium (Re), Group 7, Atomic Number 75, d-block, Mass 186.207. Sources, facts, uses, scarcity (SRI), podcasts, alchemical symbols, videos and images. Jump to main content.
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Abstract: A graphite-metal carbide-rhenium article of manufacture is provided, which is suitable for use as a component in the hot zone of a rocket motor at operating temperatures in excess of approximately 3,000 degrees Celsius. One side of the metal carbide is chemically bonded to the surface of the graphite, and the rhenium …
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It has been demonstrated that during heat treatment there was formation of a two-phase (α + β)-structure. In this case rhenium, as also chromium, vanadium, and molybdenum, is concentrated within β -phase. ... E. N. Kablov, "Physicochemical and production features of heat-resistant alloy creation containing rhenium," Vestn. Mosk. …
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The structure of molybdenum ions depends on pH values in the contacting solution 6, ... The sulphuric acid and nitric–sulphuric acid systems obtained after processing of rhenium-containing molybdenum concentrates were used for the anion exchangers testing under laboratory and industrial conditions 6, 9, 12.
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Nickel-based single-crystal superalloys are the key materials for the manufacturing and development of advanced aeroengines. Rhenium is a crucial alloying element in the advanced nickel-based single-crystal superalloys for its special strengthening effects. The addition of Re could effectively enhance the creep properties of the single …
به خواندن ادامه دهیدRhenium (Re), chemical element, a very rare metal of Group 7 (VIIb) of the periodic table and one of the densest elements. Predicted by the Russian chemist Dmitry Ivanovich Mendeleyev (1869) as chemically related to manganese, rhenium was discovered (1925) by the German chemists Ida and Walter
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The dendritic structure is not visible anymore and the local variation in the chemical composition of slowly diffusing element Re in Alloy-ReRu is 16% at the most. ... The three-dimensional morphology of topologically close packed phases in a high rhenium containing nickel based Superalloy: the three-dimensional morphology of TCP phases. …
به خواندن ادامه دهیدRhenium is one of the rarest elements in Earth's continental crust; its estimated average crustal abundance is less than 1 part per billion. Rhenium is a metal …
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The structure of the σ phase is shown to depend on the fit between the γ matrix and the σ phase and it is suggested that alloys which show good lattice fit suffer accelerated TCP precipitation. ... In this study a number of experimental second-generation alloys containing 3% rhenium are considered. The compositions, given in Table 2, …
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A series of sodium borosilicate glasses were synthesized with KReO 4 or Re 2 O 7, to 10,000 ppm (1 mass%) target Re, to assess effects of large concentrations of rhenium on glass structure and ...
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We focus attention on the difference between the dendrite structures of cobalt-free and rhenium-free VKNA-1V alloys and the VKNA-25 alloy containing these AEs. The dendrites of both alloys have a two-phase structure: the γ'-phase portions several micrometers in size are separated by interlayers of nickel-based γ-solid solution with …
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