The investigations of the crystal structure, grain structure and dielectric properties of high-temperature multiferroic Bi1-хSmxFeO3 were carried out over a wide concentration range x = 0.00-0.50.

Keywords: multiferroic crystal structure, grain structure, dielectric properties

Platinum based nanocomposite materials are widely used as catalysts for proton-exchange membrane fuel cells (PEMFC).Carbon supported pure Pt electrocatalysts were prepared by several methods including wet synthesis and electrochemical technique. The X-ray absorption measurements of pure Pt catalysts in the Pt L3 absorption edge were carried out at the Rigaku R-XAS using fluorescence mode. A change of white line intensity of XANES with changes of Pt/C particle size was found. The change of oxidation state of Pt/C nanoparticles, which may be the result of the interaction of nanoparticles with a carbon substrate, is shown. Also theoretical XANES spectra with decreasing interatomic distance Pt-Pt were calculated using FEFF8 code. It is well known that the decreasing of the Pt-Pt distance is one of the reasons of the positive influence of the catalytic activity toward the oxygen reduction reaction (ORR).

Keywords: XANES, nanoparticles, nanocatalysts, nanocomposites, composite materials

The present work is devoted to the local atomic and electronic structure of dimetacyano (DMC) molecules deposited on a Bi (111) substrate before and after irradiation by X-rays and UV light using density functional theory (DFT) and a theoretical analysis of the X-ray absorption near edge structure (XANES) spectroscopy. As a result of the calculations the low-energy structure for DMC azobenzene molecules on a Bi (111) substrate was obtained.

Keywords: local atomic and electronic structure, X-ray absorption spectroscopy, photoisomerization, density functional theory

For the first time, using modern analytical methods studied phase and impurity composition of the cathode alloys Pd-Ba, obtained by industrial technology. The concentration of harmful impurities (C, Zn, Ba, Cu) in objects of study does not exceed the standards for these materials. Transmission electron microscopy and X-ray analysis confirmed the previously observed biphasic alloys Pd-Ba, from which one phase - intermetallic compound (Pd5Ba), second - palladium (matrix), wherein the intermetallic compound is very unevenly distributed in the matrix. The object of the study was first detected undesirable phase Pd2O. It is found that in the alloys of Pd-Ba grain Pd - large (about one micron), grain phase Pd5Ba - from a few hundred nanometers to one micron. All beans there is a high density of randomly distributed dislocations. Processing methods are proposed to improve the homogeneity of the alloy.

Keywords: alloyed metal cathodes, Pd-Ba, emission properties, transmission electron microscopy, X-ray analysis, impurity composition, the coefficient of secondary electron emission

For the first time, using modern analytical methods studied phase and impurity composition of the cathode alloys Pt-Ba, obtained by industrial technology. The concentration of harmful impurities (C, Zn, Ba, Cu) in objects of study does not exceed the standards for these materials. Transmission electron microscopy and X-ray analysis confirmed the previously observed biphasic alloys Pt-Ba, from which one phase - intermetallic compound (Pt5Ba), second - platinum (matrix), wherein the intermetallic compound is very unevenly distributed in the matrix. It is found that in the alloys of Pt-Ba Pt grains - small (a few hundred nm) and grain Pt5Ba - large (make several microns) and more sophisticated. Inside there are grains Pt5Ba voltage. Processing methods are proposed to improve the homogeneity of the alloy.

Keywords: alloyed metal cathodes, Pt-Ba, emission properties, transmission electron microscopy, X-ray analysis, impurity composition, the coefficient of secondary electron emission

Using an interpenetrating polymer networks (IPN) principle in production of composite materials provides an unique possibility to regulate their both micro- and nano- structures and properties. By changing the IPN formation conditions (as a resultof polymerization and ratio of components, temperature, pressure, catalyst content, introduction of filler and or ionic group) one may obtain the material with desirable properties.Different types of IPN are prepared by using traditional polymers: polyurethanes, including nonisocyanate polyurethanes, epoxies and acrylates; non- organic fillerscan be used as the cluster system.The article discussestheir basic synthesis methods for IPNs their principal features and characteristics.

Keywords: interpenetrating polymer networks, crosslinked polymers, classification of IPN, properties of IPN

Recent advances in chemistry and technology of nonisocyanate polyurethane (NIPU) materials based on cyclic carbonate oligomers are reviewed in this paper. Reaction of the cyclic carbonate and amino groups results in β-hydroxyurethane fragments with specific properties. Primary attention is given to the hybrid materials that contain epoxy and acrylic compounds, especially materials based on renewable raw materials. Hybrid organic composites comprising of silanes are also considered. An overview of the recent publications in this field is provided with a more detailed description of achievements by the authors and their corporate employees. The use of NIPU materials as coatings, adhesives, and foams is described.

Keywords: nonisocyanate polyurethanes, cyclic carbonate oligomers, hybrid polymers

This work presents the results of investigation of one of the most widespread specimens of layered silicates minerals group - montmorillonite, that are the part of the natural dispersion of bentonite from Millerovo minefield via density functional theory (DFT) methods. The hygroscopic moistness of monoions forms of smectite group layered silicates is studied experimentally; these layered silicates are the most active components that significantly determine the properties of the dispersion as a whole. The correlation between hygroscopicity and theoretical values of inter-packet distances is established in studied samples by calculating total energies with optimization of the crystal structure.

Keywords: layered silicates, exchangeable cations, density functional theory, hygroscopicity, montmorillonite

The paper represents the results of theoretical study of molecules behavior of polar aprotonic solvent dimethyl sulphoxide on basal surfaces and in interpackage space of kaolinite. Spectral and energetic regularities of chemical bond formation are studied. Intercalation of DMSO molecules into interpackage space of kaolinite results in the shift of valence vibrations Si-O into high-frequency zone. It also results in vibration suppression of hydroxyl clusters of gibbsite layer. It proves the appearance of strong hydrogen bond between the molecules of polar aprotonic dissolvent and hydroxyl and siloxane kaolinite surfaces. The paper reveals that adsorption of DMSO molecules decreases the surface energy of kaolinite and enables its organophilicity.

Keywords: "layered aluminosilicates dimethyl sulfoxide, density functional theory, intercalation, hydroxyl surface siloxane surface kaolinite"

The investigations of the crystal structure, grain structure and dielectric properties of high-temperature multiferroic Bi1-x LaxFeO3 were carried out over a wide concentration range x = 0.00-0.50.

Keywords: multiferroic crystal structure, grain structure, dielectric properties

The investigations of the crystal structure, grain structure and dielectric properties of high-temperature multiferroic Bi1-хPrxFeO3were carried out over a wide concentration range x = 0.00-0.50.

Keywords: multiferroic crystal structure, grain structure, dielectric properties

The manuscript presents results of a study ferroelectric ceramic metaniobate lithium (PCR-61) which containing Li2O, Nb2O5 and CaO in the fallowing ratio, mass. % Li2O 10,03-10,10; Nb2O5 89,22-89,87; CaO 0,03-0,75. The most effective was the offset component in alcohol and air environments, which providing sufficiently high rate of sintering, the formation on their base high density ceramic with the most perfect crystal structure and microstructure of the equilibrium. Using the foregoing results the solid phase material was prepared by one-stage synthesis (SPS) for Tsint.1 = 820℃, τ = 5h. with followed by sintering by conventional ceramic technology (CCT) (without pressure) at a temperature Ts. = 1150℃, τ = 2h. After machining, the samples were polarized ("oil" polarization). The promising method SPS + CCT was presented. Material based on piezoelectric ceramics metaniobate lithium (PCR 61) was obtained by the SPS + CCT, close to the parameters of hot-pressed (HP) samples and can be used in electrical devices under the influence of ultra-high temperatures. The effectiveness of heterovalent modification as a method of directional changes in the properties of lithium metaniobate was shown.

Keywords: ferroelectric ceramics, metaniobates lithium, solid-phase synthesis, conventional ceramic technology, the electrical properties, high temperature technology

Synthesis of the TiO2 nanoparticles was carried out by sol-gel method. The optimal conditions for stable TiO2 gel obtaining was determined. The resulting samples were studied by IR spectroscopy. Studies have shown the presence of chemically and physically bounded water in TiO2 powders, dried at 125 ° C. Studying of the influence of the pH on the acid-base properties of the surface of the resulting TiO2 powders was performed by indicator method.

Keywords: TiO2 nanoparticles, sol-gel method, acid-base properties, indicator method, infrared spectroscopy, pH of the medium

The study of copper ion (Cu2+) environment in aqueous solution was performed by means of X-ray absorption spectroscopy. X-ray absorption spectra for various concentrations of aqueous solutions of CuCl2 were measured. The testing of near-edge fine structure approach for calculating X-ray absorption Cu K-edge spectra of copper ion (Cu2 +) coordinated complex by finite difference method for solution of Schrödinger equation were held . A model of local environment of copper ion (Cu2 +) in aqueous solutions is proposed.

Keywords: X-ray absorption spectroscopy, 3d-metals ions, aqueous solutions, local environment, finite difference method, coordination complexes

In this article we consider the use of quasi-homogeneous approximation to describe the properties of disperse systems. We used a statistical method of polymer based on the consideration of all possible structures averaged macromolecules of the same weight. The equations to assess many additive parameters of macromolecules containing their systems. Statistical polymer method allows modeling branched, cross-linked macromolecules and containing their system in a state of equilibrium or non-equilibrium state. Fractal consideration of random polymer allows you to s imulate different types of random fractals and other objects studied by the methods of fractal theory. A method of statistical polymer is not only applicable to the polymers but also to composites gels associates in other polar liquids and aggregate systems. In this paper we described the state of colloidal solutions of silica from the viewpoint of statistical physics. This approach is based on the idea consists in the fact that a colloidal solution of silicon dioxide - silica sol consists of a very large number of interacting particles in a continuous motion. It is dedicated to the study of an idealized system of colliding, but not interacting particles sol. Analyzed the behavior of silica sol, in terms of Maxwell-Boltzmann distribution was calculated and the mean free path of the colloidal particles. Based on these data, it was calculated the number of particles that can overcome the potential barrier in a collision. For modeling the kinetics of the sol-gel transition, we have discussed various approaches.

Keywords: quasi-homogeneous approximation, disperse systems, statistical polymer method, the formation of cross-links, fractal method, sol, silica sol, sol-gel transition, the mean free path

In this paper we attempt to quantitatively describe the process of diffusion of Nickel atoms to the copper substrate, taking into account the accelerated diffusion along the grain boundaries. A model experiment allows us to get guidance on the selection of the optimum thickness of the Nickel coating to ensure stable operation of wire with desired characteristics

Keywords: Nickel coating, the optimum thickness, copper wire, enhanced diffusion, diffusion coefficient, diffusion distribution of atoms, the grain boundary, modeling, task Fisher

The manuscript traced the impact of changes in the content of alkaline-earth elements on the dielectric spectra of solid solutions based on lead titanate. Two concentration areas with sharply differing nature of the manifestations of dispersion phenomena were identified. First (0.02≤α1≤0.24) is characterized by strong dispersion ε/ε0 in all temperature range and not allow to generate maximum of ε/ε0 for Curie temperature at low frequencies, the second (0.24≤α1≤0.36) - a sharp decrease of Δε in the ferroelectric phase and complete disappearance of it in the solid solutions, SS, with α1 = 0.36, indicating stabilization of the structure with the introduction of alkaline SS elements. It was found that as increased the concentration of modifiers in the compositions there is a stabilization of their structure with a gradual decrease in the phase transition temperature. Formation of two concentration areas where changes macro properties SS is undoubtedly a consequence of their correlation with the phase diagram of the studied SS, which is experiencing a transformation in the neighborhood of α1 ~ 0.24, due to the transition from two-phase to single-phase state. The results obtained by the authors can be used in the development of high-temperature (α1 0.24 ) anisotropic ferroelectric materials.

Keywords: ferroelectric piezoceramics, lead titanate, alkaline earth elements, modifiers, solid phase synthesis dielectric spectra

Ceramic materials based on solid solutions La2-xSrxMO4, where M is Ni, Fe, Co, Cu, x = 0, 2 with layered K2NiF4 structure (structure of Ruddlesden-Popper) have been synthesized and investigated. The correlation of dielectric properties with a normalized bond lengths of the metal-oxygen has been observed. The existence of nickel atoms in the 2+ oxidation state for nickelates has been shown.

Keywords: solid solutions, colossal dielectric constant, resistivity, x-ray diffraction, dielectric spectrum, XANES, low-resistivity semiconductors, the activation energy, the distortion of the coordination polyhedra, oxygen non-stoichiometry

Using modern physical and chemical methods of research, such as differential thermal analysis, scanning electron microscopy, atomic absorption spectrometry, the recovery process titanium dioxide with calcium hydride at different temperatures and the stoichiometric ratios of the raw material was studied. The influence of experimental conditions on the chemical and particle size distribution of the synthesized product have been established. The mathematical dependence of the qualitative composition of titanium powder from the reduction temperature and the stoichiometric ratio of the starting components was obtained. According to the results of the experimental data revealed that the increase in diameter of grains and reducing the specific surface area of the synthesized powder increases the content of titanium in the sample. It is shown that the main problem of obtaining titanium powder is their increased oxidation caused by high specific surface

Keywords: " titanium powder, titanium dioxide, calcium hydride, mixture, process calcium hydride-thermal reduction"

In the work presented for the first time experimental data on measurement of the ESR and impedance of a coating of manganese dioxide obtained from manganese nitrate with the addition of silver nitrate by thermolysis method. Analysis of coating (XRF, SEM, XRD) of manganese dioxide with the addition of silver show a significant decrease in the resistance of the coatings. The development of energy efficient coating of manganese dioxide is one of the key objectives in the technology of low-impedance tantalum capacitors. Obtained by thermolytic method (the processing temperature of 250 and 300 °C) coating of manganese dioxide with the addition of silver nitrate 27% solution of manganese nitrate was analyzed using the RLC. The results of studies on the effect of additives in the impregnation solution of manganese nitrate on the resistance of coatings of manganese dioxide showed the possibility of significant reduction of the resistance (15 times at a temperature of thermolysis at 250°C, 45 times at a temperature of thermolysis 300 °C) by reference to the precursor silver nitrate; raising the temperature of the thermolysis of manganese nitrate from 250 to 300°C leads to the decrease of the resistance of the coating; use freshly prepared solution of manganese nitrate leads to the decrease of the resistance of the coating.

Keywords:  manganese nitrate, silver nitrate, manganese oxide, alloying, resistance, thermolysis

In this article we consider the use of quasi-homogeneous approximation to describe the properties of disperse systems. We used a statistical method of polymer based on the consideration of all possible structures averaged macromolecules of the same weight. The equations to assess many additive parameters of macromolecules containing their systems. Statistical polymer method allows modeling branched, cross-linked macromolecules and containing their system in a state of equilibrium or non-equilibrium state. Fractal consideration of random polymer allows you to s imulate different types of random fractals and other objects studied by the methods of fractal theory. A method of statistical polymer is not only applicable to the polymers but also to composites gels associates in other polar liquids and aggregate systems. In this paper we described the state of colloidal solutions of silica from the viewpoint of statistical physics. This approach is based on the idea consists in the fact that a colloidal solution of silicon dioxide - silica sol consists of a very large number of interacting particles in a continuous motion. It is dedicated to the study of an idealized system of colliding, but not interacting particles sol. Analyzed the behavior of silica sol, in terms of Maxwell-Boltzmann distribution was calculated and the mean free path of the colloidal particles. Based on these data, it was calculated the number of particles that can overcome the potential barrier in a collision. For modeling the kinetics of the sol-gel transition, we have discussed various approaches.

Keywords: quasi-homogeneous approximation, disperse systems, statistical polymer method, the formation of cross-links, fractal method, sol, silica sol, sol-gel transition, the mean free path

In this paper we investigated the structure of the magnetic fluid based on Fe3O4 nanoparticles. Magnetic fluid based on Fe3O4 nanoparticles is used for cancer treatment, targeted drug delivery, hyperthermia, as a contrast agent in surgery, as a barrier to blood flow and others. Magnetic fluid based on Fe3O4 nanoparticles was synthesized by chemical condensation of magnetite nanoparticles. Characteristics of magnetic fluid (oxidation of iron nanoparticles size, density) were investigated using X-ray absorption spectroscopy. The changes of the antitumor effect of the magnetic fluid is associated with an increase of the particle size of the iron oxide that has a significant impact on their penetration in a tumor tissue.

Keywords: magnetic fluid, magnetite, nanoparticles, Fe3O4, oxidation state, density, antitumor activity

The paper provides information on the influence of thermodynamic prehistory (conditions for obtaining) and the processes associated with time "aging" of the samples in the dielectric properties of the alkaline-earth elements modified lead titanate ceramics. The data shows a dielectric stability of solid solutions (SS) with a high content of alkaline-earth elements (almost independently of the Curie temperature of sintering temperature). This is supported by the fact of reproduction the character of dielectric spectra in SS (α1≥0.22) unlike changed profile curves ε / ε0 (T) |f SS (α1 = 0.04). The splitting of the maxima ε / ε0 (T) |f, obtained on the same samples after 7 months (April 2015) after the initial measurements (September 2014) is the result of degradation of solid solutions close to PbTiO3, probably due to begin the process of self-destruction ceramics.

Keywords: ferroelectric ceramics, lead titanate, alkaline-earth elements, thermodynamic prehistory, dielectric properties, the effects of degradation

In this work we continue the study of ferroelectric compositions of different composition – basics of functional materials piezo technical destination. Considered are solid solutions (TR) binary system (1-x) PbZrO3 – x PbTiO3 (PZT), up to the present time remaining as base of almost all commercially available functional materials. Studied the impact of technological regimes on the properties of solid solutions with 0.135 ≤ x ≤ 0.145, 0.16 ≤ x ≤ 0.18, 0.37 ≤ x ≤ 0.58, 0.75 ≤ x ≤ 0.77, 0.795 ≤ x ≤ 0.805, the research concentration step Δx = 0.0025. The sintering temperature was varied from 1200 °C to 1240 °C, the duration of the extracts 2 and 3 hours. It is established that the structural parameters remain almost constant under variations of conditions in process their production in all ranges (rhombohedral, tetragonal and morphotropic) of the concentrations, and the change of relative dielectric permittivity of unpolarized samples is not more than (10÷12) %. It was shown that the study of solid solutions of multicomponent systems on the basis of lead zirconate titanate is possible with the minimal concentration of the step ∆x = 0.25 mol.%. Application of the considered techniques in the fabrication of functional materials for various purposes provides high reproducibility of their parameters. Obtained results can be useful for development of new ferro-piezoelectric materials on the basis of other complex oxides.

Keywords: solid solution, lead zirconate titanate, technology, crystal structure, dielectric permittivity

The values the frequencies of the stretching vibrations of nitrit-, nitrat- and perclorat- anions in molten salts of alkali metals and their point group symmetry. There is a correlation with an increase in the frequency of symmetry.

Keywords: frequency Raman spectra, Raman spectra, melts, nitrites, nitrates, perchlorates of alkali metals, binary salt system frequency Raman spectra, Raman spectra, melts, nitrites, nitrates, perchlorates of alkali metals, binary salt system