RAS Institute of Metallurgy

Yekaterinburg, Russia

RAS Institute of Metallurgy

Yekaterinburg, Russia
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Conspectus High temperature electrochemical devices such as solid oxide fuel cells (SOFCs) and oxygen separators based on ceramic materials are used for efficient energy conversion. These devices generally operate in the temperature range of 800-1000 °C. The high operating temperatures lead to accelerated degradation of the SOFC and oxygen separator materials. To solve this problem, the operating temperatures of these electrochemical devices must be lowered. However, lowering the temperature is accompanied by decreasing the ionic conductivity of fuel cell electrolyte and oxygen separator membrane. Therefore, there is a need to search for alternative electrolyte and membrane materials that have high ionic conductivity at lower temperatures. A great many opportunities exist for molten oxides as electrochemical energy materials. Because of their unique electrochemical properties, the molten oxide innovations can offer significant benefits for improving energy efficiency. In particular, the newly developed electrochemical molten oxide materials show high ionic conductivities at intermediate temperatures (600-800 °C) and could be used in molten oxide fuel cells (MOFCs) and molten oxide membranes (MOMs). The molten oxide materials containing both solid grains and liquid channels at the grain boundaries have advantages compared to the ceramic materials. For example, the molten oxide materials are ductile, which solves a problem of thermal incompatibility (difference in coefficient of thermal expansion, CTE). Besides, the outstanding oxygen selectivity of MOM materials allows us to separate ultrahigh purity oxygen from air. For their part, the MOFC electrolytes show the highest ionic conductivity at intermediate temperatures. To evaluate the potential of molten oxide materials for technological applications, the relationship between the microstructure of these materials and their transport and mechanical properties must be revealed. This Account summarizes the latest results on oxygen ion transport in potential MOM materials and MOFC electrolytes. In addition, we consider the rapid oxygen transport in a molten oxide scale formed on a metal surface during catastrophic oxidation and show that the same transport could be used beneficially in MOMs and MOFCs. A polymer model explaining the oxygen transport in molten oxides is also considered. Understanding the oxygen transport mechanisms in oxide melts is important for the development of new generation energy materials, which will contribute to more efficient operation of electrochemical devices at intermediate temperatures. Here we highlight the progress made in developing this understanding. We also show the latest advances made in search of alternative molten oxide materials having high mixed ion electronic and ionic conductivities for use in MOMs and MOFCs, respectively. Prospects for further research are presented. © 2017 American Chemical Society.

Ivanova L.D.,RAS Institute of Metallurgy
Semiconductors | Year: 2017

Based on the analysis of current scientific publications, materials for thermoelectric devices operating at different temperatures within 100–1300 K are reviewed. The main attention is paid to the fabrication of nanostructured thermoelectric materials. It is established that the most promising techniques for the synthesis of such materials are melt spinning, spark plasma sintering, and extrusion. © 2017, Pleiades Publishing, Ltd.

Kashlev Y.A.,RAS Institute of Metallurgy
Physica B: Condensed Matter | Year: 2017

Evolution of vibration relaxation of hydrogen atoms in metals with the close-packed lattice at high and medium temperatures is investigated based on non-equilibrium statistical thermodynamics, in that number on using the retarded two-time Green function method. In accordance with main kinetic equation – the generalized Fokker- Plank- Kolmogorov equation, anharmonism of hydrogen atoms vibration in potential wells does not make any contribution to collision effects. It influences the relaxation processes at the expense of interference of fourth order anharmonism with single-phonon scattering on impurity hydrogen atoms. Therefore, the total relaxation time of vibration energy of system metal-hydrogen is written as a product of two factors: relaxation time of system in harmonic approximation and dimensionless anharmonic attenuation of quantum hydrogen state. © 2017 Elsevier B.V.

Belousov V.V.,RAS Institute of Metallurgy
MRS Communications | Year: 2013

Most important advances of the last years in research and development of oxygen ion transport membrane (ITM) materials based on solid or liquid Bi2O3 are briefly given. Special attention is paid to the transport properties of novel NiO/δ-Bi2O3 and In2O3/δ-Bi2O3 ceramic and ZnO/Bi2O3 solid/liquid composites. These composites show promise for use as ITM with the oxygen permeation rate comparable with that of the state-of-the-art membrane materials. The in situ Bi2O3 melt crystallization and grain boundary wetting methods of formation of the gas-tight composites are considered. © 2013 Materials Research Society .

Nechaev Y.S.,RAS Institute of Metallurgy
International Journal of Hydrogen Energy | Year: 2011

Thermodynamic and experimental backgrounds of the condensed hydrogen storage problem are considered. It results in developing an effective method of producing a high-density solid hydrogen carrier by means of hydrogen intercalation in carbonaceous nanomaterials at relevant temperatures and pressures (at the cost of the hydrogen association energy). This is a much more technological method, in comparison with the current megabar compression dynamic and static methods. As is also shown, one of the known processes of chemisorption of hydrogen in some carbonaceous nanostructures can be related to formation of graphane-like (i.e., carbohydride-like) nanoregions. By using gravimetric and electron microscopy data, the density values ( ρH=0.7±0.2g(H2)/cm3(H 2),ρH=0.28±0.08g(H2)/cm3(system)), of the intercalated solid molecular (i.e., reversible) hydrogen in graphane-like nanofibers (≥ 17 wt% H2) has been defined. It corresponds to a much more efficient hydrogen storage technology, in comparison with the current ones, and relevance to the U.S. DOE requirements and targets for 2015. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Leontyev V.,RAS Institute of Metallurgy
Physica Status Solidi (B) Basic Research | Year: 2013

Nanoparticles of pure Ni and Ni-Cu solid solution were synthesized by the sol-gel method at 400-600°C. The particle sizes and values of specific surface of powders were dependent on the synthesis temperature. The magnetization of the obtained powders was studied using a high-temperature magnetic balance. The Curie temperature for particles of pure nickel did not depend on their size but the specific magnetization at 300K decreased linearly with increasing specific surface area of particles. For particles of the Ni-Cu binary solid solutions, the Curie temperature and values of magnetization increased with decreasing particle size for particles with diameters up to values less than 100nm. The amount of adsorbed copper on the particles surface, the change of nickel concentration in the volume of the particles and the Curie temperatures, depending on the Cu (Ni) concentration in a volume of particles, were calculated using the Gibbs equation. The calculations made in the framework of a perfect solution showed qualitative agreement between experimental and calculated values of the Curie temperature for the system Ni-Cu. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ryltsev R.E.,RAS Institute of Metallurgy | Chtchelkatchev N.M.,Moscow Institute of Physics and Technology | Ryzhov V.N.,Moscow Institute of Physics and Technology
Physical Review Letters | Year: 2013

We investigate glassy dynamical properties of one-component three-dimensional system of particles interacting via pair repulsive potential by the molecular dynamic simulation in the wide region of densities. The glass state is superfragile and it has high glass-forming ability. The glass transition temperature Tg has a pronounced minimum at densities where the frustration is maximal. © 2013 American Physical Society.

Pogorelova A.V.,RAS Institute of Metallurgy
Proceedings of the 10th (2012) ISOPE Pacific/Asia Offshore Mechanics Symposium, PACOMS 2012 | Year: 2012

This paper studies the three-dimensional unsteady problem of the hydroelastic behavior of a floating infinite plate under the impact of waves generated by moving loads on ice plate in conditions of sloped bottom. An analytic solution of the problem is found by integral transformations and asymptotic expansions. The amplitude is analyzed for various values of bottom slope, basin depth, plate thickness, vehicle length, deceleration and acceleration coefficients. © 2012 by International Society of Offshore and Polar Engineers.

Belousov V.V.,RAS Institute of Metallurgy
Corrosion Science | Year: 2010

An electrochemical mechanism of hot corrosion of the Bi2O3-deposited copper is proposed. Oxygen ion transport across the oxide scale with liquid-channel grain-boundary structure (LGBS) is the rate-limiting step in the overall mechanism. The calculated and experimental values of the rate constant for hot corrosion of Bi2O3-deposited copper are of the same order of magnitude, which shows agreement between theory and experiment. © 2009 Elsevier Ltd. All rights reserved.

Barinov S.M.,RAS Institute of Metallurgy
Russian Chemical Reviews | Year: 2010

The topical problems in chemistry and technology of materials based on calcium phosphates aimed at both the replacement of damaged bone tissue and its regeneration are discussed. Specific features of the synthesis of nano-crystalline powders and the fabrication of ceramic implants are described. Advances in the development of porous scaffolds from resorbable and osteoconductive calcium phosphates and of hybrid composites that form the basis of bone tissue engineering are considered. © 2010 Russian Academy of Sciences and Turpion Ltd.

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