Rhenium Content Research Articles

Microstructure, hardness and wear resistance of plasma-sprayed and electron beam remelted Ni-Cr-Re coatings on Inconel 625

This paper presents research on the microstructure as well as mechanical properties of electron remelting of air plasma spraying (ASP) layers made of Ni-Cr-Re alloy with varying amounts of rhenium on Inconel 625. Initially, Ni-20 %Cr powder alloys with 10, 20 and 30 % (by weight) rhenium content were prepared and applied to the Inconel by ASP. Then, the air plasma sprayed coatings were remelted by electron beam under different parameters. The remelting by electron beam improved the density and smoothness of the ASP coatings. The remelted coatings were characterized by a dendritic microstructure. Wear tests revealed that the sprayed and electron-remelted coatings had a lower weight loss for higher Re content and that the hardness the remelted coating increased with increasing Re content.

Rhenium and related valuable metals in the oil shales of the Volga basin

The results of study of the content of rhenium and other valuable metals in the oil shales of the Volga basin are presented. The new data on precise determination of Re, Co, Ni, Cu, Zn, U and other metals by inductively coupled plasma mass spectrometry have been published. The content of the studied metals were compared with clarks in carbonaceous shales. The association of metals with rhenium (Mo, U, Co, Ni, Cu, Zn, Se, Ag, Sb) has been isolated in oil shales. The organic matter of oil shales acts as a rhenium concentrator, and apparently Mo, U. The preferred petrographic type of oil shales for the concentration of rhenium in them is the colloalginite-vitrinite-clay type. The rhenium-bearing and metalliferous content of the Volga shales is compared with the contents of rhenium and a number of other valuable metals in dictyonema shales of the Baltic sedimentary basin.

The Formation Conditions of the Volga Basin Oil Shales in Relation to Their Metallogeny on Rhenium and Other Valuable Elements

The Volga oil shales are located on the Russian platform and represent a potential non-traditional and promising source of rhenium and other valuable metals. Concentrations of rhenium at the level of industrial types of ores have been identified at the Perelyubskoe and Kotsebinskoe deposits. The complex of lithological and geochemical studies suggests that the metallogeny of the Volga oil shales is associated with the influence of volcanism and anoxic conditions during the sedimentation period. The main criteria have been identified by which high concentrations of rhenium in the Volga oil shales can be predicted: the content of organic carbon, molybdenum, and the DOPr indicator. Based on the analyzed data, promising layers have been identified for the Perelyubskoe and Kotsebinskoe deposits to detect industrial concentrations of rhenium.

The Influence of Rhenium Content on Helium Desorption Behavior in Tungsten-Rhenium Alloy.

To investigate the influence of different rhenium contents on the helium desorption behavior in tungsten-rhenium alloys, pure tungsten and tungsten-rhenium alloys were irradiated with helium under the same conditions. All irradiated samples were characterized using TDS and DBS techniques. The results indicate that the addition of rhenium can reduce the total helium desorption quantity in tungsten-rhenium alloys and slightly accelerate the reduction in the concentration of vacancy-type defects accompanying helium dissociation. The desorption activation energy of helium is approximately 2 eV at the low-temperature peak (~785 K) and about 4 eV at the high-temperature peak (~1475 K). An increase in rhenium content causes the desorption peak to shift towards higher temperatures (>1473 K), which is attributed to the formation of the stable complex structures between rhenium and vacancies. Besides, the migration of He-vacancy complexes towards traps and dynamic annealing processes both lead to the recovery of vacancy-type defects, resulting in a decrease in the positron annihilation S parameters.

Mechanical properties of Mo-Re alloy based on first-principles and machine learning potential function

This study utilizes first principles calculations of density functional theory and Spectral Neighbor Analysis Potential (SNAP) machine learning potential to investigate the influence of rhenium concentration and temperature on the fundamental mechanical properties of Molybdenum-Rhenium alloy. The Mo1−xRex alloys (x = 0.0625–0.5) are constructed using a special quasi-random structure BCC model. The optimized geometries and lattices are used to calculate elastic constants and derivate mechanical parameters, including Bulk modulus, Young's modulus, Shear modulus, etc. The results show that with the increase of rhenium content, the mechanical properties of Mo1−xRex alloy are significantly improved, and higher than pure molybdenum, the best properties are reached at x(Re) = 0.3125. On the other hand, by analyzing the ratio of bulk modulus to shear modulus (B/G) and Poisson's ratio, the alloying of rhenium can also improve the ductility of molybdenum rhenium alloy. To address the challenge of calculating the high-temperature mechanical properties of Molybdenum-Rhenium alloy, a machine learning potential was developed within a training set called Spectral Neighbor Analysis Potential (SNAP). We accurately predicted the bulk modulus, shear modulus, Young's modulus, and Poisson's ratio of Molybdenum-Rhenium alloy over the temperature range of 300–1300 K. Additionally, we provided an accurate description of how temperature affects the mechanical properties and solubility of Molybdenum-Rhenium alloy. This approach aims to overcome the limitations associated with traditional methods and provide accurate predictions of the alloy's mechanical behavior at elevated temperatures.

Net effect of chemical erosion in a tropical basin on carbon cycle: Constraints from elemental and sulfur isotopic composition of the Mahanadi river water

Chemical erosion in river basins influence the climate by both consuming (via silicate erosion and carbon burial) and releasing (via H2SO4-mediated carbonate weathering and organic oxidation) atmospheric CO2. Net erosional effect of a basin on carbon cycle, therefore, requires precise rate assessment of all these pathways; combined data for the four processes for a given basin are sparse. In this contribution, we have quantified these process intensities for a large tropical basin (Mahanadi river) from the eastern part of India using new time-series (weekly) data for dissolved major ions and sulfur isotopes, and compiled data for rhenium concentrations and particulate carbon isotopes for the basin. The discharge-weighted silica concentrations (∼215 μM) of these samples is higher than that reported as global average for rivers (∼145 μM), indicating intense silicate erosion in the basin. The δ34S of the riverine sulfates vary between 8.8 ‰ and 17 ‰, with a discharge-weighted average of 12 ± 4 ‰ (global riverine value ∼4.4 ± 4.5‰). Temporal changes in concentrations for most of the elements (and δ34S) show relatively higher (enriched) values during lean-flow stages. Mass balance calculations involving Ca, Mg and Si values confirm that these seasonal changes are mainly due to increase (by 18 ± 9%) of groundwater supply to the stream during non-monsoon seasons. The silicate-derived cations (Catsilicate) for the Mahanadi show minimal changes during monsoon (36 ± 5%) and non-monsoon (33 ± 8%) seasons. These data correspond to a CO2 consumption rate of 2.4 ± 1.6 tC/km2/yr, which is about two times higher than that reported for global rivers. Comparison of δ34S values of riverine sulfate with its possible sources computes the relative supply of sulfates from atmospheric deposition (38%), gypsum (46%), and sulfides (16% (a lower limit)) to the river. The minimal contribution via sulfide oxidation confirms low CO2 release (0.1 ± 0.1 tC/km2/yr) in this basin through sulfuric-acid mediated carbonate weathering. Average rhenium for this river is 5 ± 3 pmol/kg. The source apportionment using S/Re and Na/Re ratios indicates that 85 ± 10% of the Re is derived through organic oxidation. The rhenium data are used to estimate the CO2 release rate (0.50 ± 0.57 tC/km2/yr) by oxidation of petrogenic carbon, which is higher than the estimated organic burial rate (0.27 ± 0.12) for the basin. The estimated four erosion rates confirm a net negative (∼ − 2.1 ± 1.7 tC/km2/yr) effect of chemical erosion in the Mahanadi basin on the CO2 budget. Low sulfide-oxidation in this supply-limited regime is possibly linked to limited exposure of fresher minerals, whereas high silicate erosion in the basin is consistent with its silicate-dominated lithology and tropical climate.

Designing brazing filler metal for heat-resistant nickel alloys of new generation marine gas turbines

The object of research is the processes of the formation of brazed joints and the stressed state. The subject of research is structure, chemical composition, long-term high-temperature strength at a temperature of 900 °C, speed of high-temperature salt corrosion. Existing brazing filler metals have a high-temperature performance of 40–50 % of the performance of the SM93-VI and SM96-VI alloys. Despite this, brazing is the main technique of joining modern heat-resistant cast alloys. Therefore, the development of new brazing filler metals that ensure the formation of joints with increased long-term high-temperature strength is relevant. Ship gas turbine blades operate at a temperature of 900 °C. The purpose of the development of the new SBM-4 brazing filler metal is to achieve long-term high-temperature strength of brazed joints at a temperature of 900 °C at the level of 85–90 % of the strength of heat-resistant alloys SM93-VI and SM96-VI. A two-stage method was used in the development of SBM-4 brazing filler metal. At the first stage, the chemical composition of the brazing filler metal base was determined, taking into account the peculiarities of operating conditions of the blades of marine gas turbine engines and the achievements of materials science of heat-resistant alloys. At the second stage, the depressant and its necessary content were selected. Computer software was used to determine the distribution between the γ- and γ'-phases, taking into account the participation of each element in both dispersion and solid-solution strengthening. Rational limits of concentrations of alloying elements were determined. The criterion was the minimum susceptibility of brazing filler metal to the formation of brittle phases, taking into account the influence of chromium, rhenium, and tantalum concentrations on resistance to high-temperature salt corrosion and high-temperature performance. The long-term strength of SM93-VI and CM96-VI alloys brazed with SBM-4 brazing filler metal is 89–91 % of the strength of the base metal. Technologies of brazing and correction of casting defects have been introduced into production.

High rates of rock organic carbon oxidation sustained as Andean sediment transits the Amazon foreland-floodplain

The oxidation of organic carbon contained within sedimentary rocks ("petrogenic" carbon, or hereafter OCpetro) emits nearly as much CO2 as is released by volcanism, thereby playing a key role in the long-term global C budget. High erosion rates in mountains have been shown to increase OCpetro oxidation. However, these settings also export unweathered material that may continue to react in downstream floodplains. The relative importance of OCpetro oxidation in mountains versus floodplains remains difficult to assess as disparate methods have been used in the different environments. Here, we investigate the sources and fluxes of rhenium (Re) in the Rio Madre de Dios to quantify OCpetro oxidation from the Andes to the Amazon floodplain using a common approach. Dissolved rhenium concentrations (n = 131) range from 0.01 to 63 pmol L-1 and vary depending on lithology and geomorphic setting. We find that >75% of the dissolved Re derives from OCpetro oxidation and that this proportion increases downstream. We estimate that in the Andes, OCpetro oxidation releases 11.2+4.5/-2.8 tC km-2 y-1 of CO2, which corresponds to ~41% of the total OCpetro denudation (sum of oxidized and solid OCpetro). A Re mass balance across the Rio Madre de Dios shows that 46% of OCpetro oxidation takes place in the Andes, 14% in the foreland-lowlands, and 40% in the Andean-fed floodplains. This doubling of OCpetro oxidation flux downstream of the Andes demonstrates that, when present, floodplains can greatly increase OCpetro oxidation and CO2 release.

Influence of Re addition amount on structure, mechanical, oxidation as well as corrosion behaviors of WC-15Co cemented carbide

Various contents of rhenium (Re) were successfully doped into WC-15Co hard alloys. After that, some professional analytical instruments such as SEM, XRD, hardness tester, muffle furnace, and electrochemical workstation were chosen to appraise their microstructures and properties. By comparison, rhenium doping could greatly change the high-temperature hardness and high-temperature antioxidant capacity of WC-15Co hard alloys. With the increase of rhenium doping, the high-temperature hardness and high-temperature antioxidant capacity of WC-15Co hard alloys continue to improve. In the meantime, the KIC revealed a max of 14.57 MPa·m1/2 and the flexural strength reached up to 3367 MPa at rhenium doping of 4.5 wt%. Moreover, the icorr of hard alloys in acid and alkaline environments first decreased and then increased as the increase of rhenium doping, indicating that the optimal rhenium doping was within the range of 1.5%–4.5%.Thus, an appropriate amount of rhenium doping was a good additive for optimizing the overall performance of hard alloys.

Electrochemical obtaining of rhenium-molybdenum alloys

Based on the study of current-voltage dependences during the co-deposition nt electrical reduction of rhenium and molybdenum from sulfuric acid on a Pt electrode, conditions for deposition of alloy nanocoatings of the Re-Mo system were established. The influence of various factors, such as the content of components in the electrolyte, current density, temperature, acidity of solutions, etc., on the composition and quality of coatings was studied. It was established that with an increase in the content of rhenium in the electrolyte and increase of current density, the content of rhenium in the alloy is increased. The composition and morphology of Re-Mo thin films electrodeposited on a platinum electrode were analyzed. The phase composition of the obtained films was determined by XRD using a diffractometer, and the study of the morphology of Re-Mo films on platinum and nickel substrates was performed using a scanning electron microscope. Based on this study, the optimal conditions for the deposition molybdenum with rhenium and the required composition of the electrolyte were selected. For the obtaining rhenium-molybdenum alloys containing 50-80 wt.% Re, the following electrolyte composition can be recommended: 0.0015M Na2MoO4 + 0.0035M KReO4 + 2M H2SO4, pH 0.4; t = 75°C, electrode - Pt.

Plasma Rhenium and Selenium Concentrations After Repeated Daily Oral Administration of Rhenium(I)-diselenoether in 4T1 Breast Tumor-bearing Mice.

Rhenium(I)-diselenoether (Re-diSe) is a compound combining a rhenium tricarbonyl(I) core with a diselenide ligand. A high dose of 60 mg/kg had a pro-tumor effect in a previous study, in non-immune deficient 4T1 tumor-bearing mice, while doses of 1 and 10 mg/kg did not affect tumor growth, after repeated oral administrations. This study aimed to examine the tumor effects of a lower dose of 0.1 mg/kg with the same experimental design and to assay plasma Re and Se concentrations. Syngenic BALB/cByJ (JAX) mice were orthotopically inoculated with 4T1 mammary breast cancer cells. Re-diSe was daily administered orally for 23 days at doses of 0.1, 1, and 10 mg/kg, whereas controls received no treatment. Tumor and mice weights were measured at the end of the experiment. Plasma Re and Se concentrations were assayed by an inductively coupled plasma sector field mass spectrometry instrument (ICP-sf-MS). The weight of the tumors did not vary in treated versus non-treated mice. The limit of detection (LOD) of Re was 0.34 nmol/l. Plasma Re concentrations were 14±20 nmol/l at doses of 0.1 mg/kg, and increased at higher doses, up to 792±167 nmol/l at doses of 10 mg/kg. Plasma Se concentrations were significantly increased in mice treated with the dose of 0.1 mg/kg (4,262±1,511 nmol/l) versus controls (1,262±888 nmol/l), but not from 0.1 to 1 mg/kg, nor from 1 to 10 mg/kg. The 0.1 mg/kg dose of Re-diSe resulted in detectable plasma Re concentrations and significantly increased plasma Se concentrations. In the future, doses as low as 0.1 mg/kg of Re-diSe will be tested, exploring its potential immune interest as a metronomic schedule of treatment, but in mouse models that readily develop extensive metastatic disease.

The Effect of Rhenium Content on Microstructural Changes and Irradiated Hardening in W-Re Alloy under High-Dose Ion Irradiation.

An amount of 100 dpa Si2+ irradiation was used to study the effect of transmutation rhenium content on irradiated microscopic defects and hardening in W-xRe (x = 0, 1, 3, 5 and 10 wt.%) alloys at 550 °C. The increase in Re content could significantly refine the grain in the W-xRe alloys, and no obvious surface topography change could be found after high-dose irradiation via the scanning electron microscope (SEM). The micro defects induced by high-dose irradiation in W and W-3Re alloys were observed using a transmission electron microscope (TEM). Dislocation loops with a size larger than 10 nm could be found in both W and W-3Re alloy, but the distribution of them was different. The distribution of the dislocation loops was more uniform in pure W, while they seemed to be clustered around some locations in W-3Re alloy. Voids (~2.4 nm) were observed in W-3Re alloy, while no void was investigated in W. High-dose irradiation induced obvious hardening with the hardening rate between 75% and 155% in all W-xRe alloys, but W-3Re alloy had the lowest hardening rate (75%). The main reasons might be related to the smallest grain size in W-3Re alloy, which suppressed the formation of defect clusters and induced smaller hardening than that in other samples.

Marine osmium isotopic composition reconstructed from the early Permian umber deposit in the Japanese accretionary complex

• Re-Os isotopes of early Permian umbers in Japan were analyzed. • Oxidative Mn-oxides prevented Re fixation into the Kunimiyama umbers. • 187 Os/ 188 Os values of early Permian seawater ranged from 0.523 to 0.676. Strata-bound ferromanganese (Fe–Mn) deposits (umbers) are thought to have formed by precipitation of Fe–Mn oxyhydroxides derived from seafloor hydrothermal activity at a mid-oceanic ridge. Fe–Mn oxyhydroxides effectively adsorb various elements (e.g., P, V, As, rare earth elements, and Os) dissolved in seawater. Of these elements, osmium (Os) is particularly important for reconstructing the Earth’s surface environment during formation of the deposits. Here we report the Os and rhenium (Re) contents and marine Os isotopic ratio ( 187 Os/ 188 Os) i of the early Permian reconstructed from the Kunimiyama umber deposit in the Northern Chichibu Belt, central Shikoku, southwest Japan. The Kunimiyama umbers exhibit comparable to slightly lower Os (42–183 ppt) and much lower Re (1.3–49 ppt) contents than other umbers in Japanese accretionary complexes and modern seafloor metalliferous sediments, the latter of which are regarded as umber precursors. The ( 187 Os/ 188 Os) i ratio of the Kunimiyama umbers is 0.523–0.676, which is comparable to or slightly higher than the values of the middle to Late Cretaceous and early Paleogene. This work is the first report of seawater Os isotope ratios in the Panthalassa Ocean of the early Permian, representing an important achievement in understanding the marine Os isotopic record of the Paleozoic Era.

Simulation study on uniaxial tensile mechanical and thermal properties of rhenium tungsten alloys

As an important potential first wall material in fusion reactor, tungsten will be irradiated by 14.1 MeV fusion neutron and then transmutated to rhenium, osmium, and tantalum during service. Due to rhenium is the main of transmutation products, which will affect the mechanical and thermal properties of the tungsten matrix. Based on this, in this work, the Young's Modulus and thermal properties of W-Re alloys with different rhenium contents were calculated by using the first principle calculations. Then, the uniaxial tensile processes in [100], [110], [111] and [211] directions were simulated by molecular dynamic simulation method. The results show that the tensile strength of W-Re alloy decreases gradually with the increase of rhenium content. With the increase of the rhenium content, the heat capacity of the material will decrease, and the thermal expansion coefficient increases.

Evidences of the non-stoichiometry and control of the composition of the cluster-based solid solution K6[Re6-xMoxS8(CN)5] (x=2.75–3.63)

In this work, we investigated a high-temperature reaction between ReS2, MoS2 and KCN resulting in the formation of the cluster-based K6[Re6-xMoxS8(CN)5] solid solution. The crystal structure is based on chains of [Re6-xMoxS8(CN)6] cluster units. It was found that both the sintering temperature of starting sulfides and the reaction temperature with KCN have an influence on the composition of the product allowing x to be varied within the range x ​= ​2.75–3.63. The molar ration of ReS2:MoS2:KCN loaded composition is fixed to 3:3:14 in all experiments. Energy dispersive spectroscopy (EDS), powder X-ray diffraction (PXRD) and high-resolution electrospray (ESI) mass spectrometry were used to characterize the solid solution K6[Re6-xMoxS8(CN)5]. It was shown by mass spectrometry that the solid solution with fractional x contains anions based on the {Re4Mo2S8}, {Re3Mo3S8} and {Re2Mo4S8} cluster cores in different proportions depending on the above-mentioned factors. Particularly, the rise of the temperature of the synthesis or temperature of sintering of metal sulfides led to increase of the rhenium content in the solid solution.

Superalloys - Characterization, Usage and Recycling

Superalloys are a group of alloys developed for use during long-term heat exposure above 650 °C. Properties and applications of superalloys are described in the present work. The work includes statis-tics about superalloys demand, market value and the current price. Division of superalloys according to basic element is mentioned. Nickel-based superalloys are further divided into two groups accord-ing to their use. Afterwards, the paper is focused mainly on nickel-based superalloys. Examples of nickel-based superalloys are listed in the work. Recycling possibilities of nickel-based superalloys are stated and analysed. General scheme of processing nickel-based superalloy scrap with regard to the content of rhenium is proposed and shortly discussed. The best-known companies dealing with sup-eralloy scrap recycling are mentioned further.

Introduction and calculation of interaction coefficients in solvent extraction of rhenium from molybdenite

In this research, a new concept called interaction coefficient in solvent extraction was introduced. Among effective parameters on rhenium extraction, organic phase to aqueous phase ratio, TBP concentration, and pH were selected as main parameters. Experiments were designed according to Response Surface Method using Minitab software. Rhenium and molybdenum concentrations were measured using Atomic Absorption Spectrometry. Rhenium’s maximum extraction was 93.8 % at pH = 0.5, [TBP] = 2.54 mol/L and, organic to aqueous phase ratio of 2:1, and molybdenum extraction under these conditions was nearly 40 % on average. The results obtained from experiments using Minitab software showed that there is a dependence between pH, O/A phase ratio and TBP concentration. For example, the related equations for the recovery percent relation to TBP concentration in the independent state is equal to ∂R∂TBP=A+0.31(TBP) and in the dependent state is equal to ∂R∂TBP=2.7960+0.31TBPC+C′TBP.

Concentration-runoff relationships of contrasting small mountainous rivers in the Pacific Northwest, USA: Insights into the weathering of rhenium relative to other weathering products

This study examines dissolved rhenium (Re) concentrations as a function of water runoff using river samples from two contrasting mountainous watersheds, the Eel and Umpqua Rivers in the Pacific Northwest, USA. These watersheds share many key characteristics in terms of size, discharge, climate, and vegetation, but they have a 15-fold difference in sediment yield due to differences in their tectonic setting and uplift and erosion rates. We evaluate concentration-runoff (C-R) relationships and ratios of coefficients of variation (CVC/CVR) for major cations, anions, dissolved inorganic carbon, selected trace elements including Re, and 87Sr/86Sr ratios. Recent research outlines the potential of Re to serve as a tracer for the oxidation of ancient/fossil organic matter because of its close association with petrogenic carbon (OCpetro) in rocks. In both the Eel and Umpqua Rivers, our measurements show that Re behaves similarly to major weathering derived-solutes corrected for atmospheric input, such as Ca2+*, Mg2+*, and Na+* with modest dilution across all tributaries with increasing runoff. Rhenium behaves dissimilarly from other trace elements, such as Mo and U, and is also dissimilar to biologically-cycled nutrients, such as NO3–, PO43−, and K+*, suggesting differences in sources, solute generation mechanisms, and flowpaths. Rhenium behavior is also distinct from that of colloids, which have increasing concentrations with increasing runoff. We find that Re and sulfate corrected for atmospheric input (SO42−*) have distinct C-R relationships, in which SO42−* undergoes greater dilution with increasing runoff. This implies that Re is not dominantly sourced from sulfide weathering, which leaves primary bedrock minerals and OCpetro hosted in bedrock of these watersheds as the likely dominant sources of dissolved Re release. At mean discharge, Re concentration in the Eel river (3.5 pmol L-1) is more than two times greater than Re concentrations in the Umpqua River (1.5 pmol L-1). Furthermore, comparison of two tributary watersheds with similar bedrock but marked differences in erosion rates show higher Re concentrations in Bull Creek (erosion rate of 0.5 mm yr−1) relative to Elder Creek (erosion rate of 0.2 mm yr−1). The results of this study suggest that dissolved Re in the Eel and Umpqua River basins is likely derived from primary mineral dissolution or OCpetro oxidation, and Re fluxes are higher in areas with higher erosion rates, suggesting that tectonic setting is one factor that controls Re release and therefore OCpetro oxidation.

Extraction of Rhenium and Osmium from Lead Technogenic Raw Materials of Copper Production.

Lead sludge from copper production is a source of rare metals, such as rhenium and osmium, whose content reaches 0.06–0.08% and 0.0025–0.0050%, respectively. The base of the sludge consists of lead sulfate. A method of reductive smelting of lead sludge from copper smelting production at 1000–1100 °C has been developed. Coke was used as a reducing agent and sodium sulfate as a slag-forming material. Optimal conditions for selective extraction of rare metals in smelting products were found: osmium in the form of metallic form into raw lead and rhenium in the form of perrhenate compound Na5ReO6 into sodium-sulfate slag. The developed technology makes it possible to extract rhenium with a high degree of extraction in the form of water-soluble compounds for the subsequent production of commercial salts of rhenium by the known hydrometallurgical methods. The content of rhenium in the slag phase is 0.18–0.25%, with its initial content in the slime of 0.06–0.08%. The degree of rhenium concentration at the first stage of processing is 3–3.2 times in the form of water-soluble perrhenate. Osmium and lead do not form solid solutions; osmium in crude lead is mainly concentrated in the lower zones of lead. A method of obtaining a concentrate containing 53–67% osmium from raw lead with an initial content of 0.0025–0.0050% in the slurry and a concentration number of 13,000–21,000 times has been proposed.

Effect of Magnetic Field on Electrodeposition and Properties of Cobalt Superalloys

The paper presents an effect of applying and directing a constant magnetic field on electrodeposition and magnetic properties of refractory metal alloys (W, Mo, Re) with cobalt deposited from citrate-pyrophosphate electrolytes. A mathematical model is presented that describes the creation of convective flows due to the micro-MHD effect in near-surface layers during electrodeposition of a ferromagnetic alloy in a magnetic field. It has been found that the greatest influence of the magnetic field applying on the electrodeposition of alloys under investigation is observed for rhenium ones, that is, there is a decrease in the rhenium content from 40 to 8 at.% (compared with deposition without magnetic field) and a halving of crystallite sizes. The magnetic properties of the resulting coatings depend on the nature of the refractory metal and can vary over a wide range.