Crystal structure and oxygen nonstoichiometry of oxides in the Ba-Me-Me’-Y-O (Me, Me’=Co, Fe) system

Polycrystalline BaМe1-xYxO3-δ(Me=Co, Fe) samples were synthesized by a conventional route and glycerol-nitrate technique. According XRD patterns of single phase solid solutions BaCo1-xYxO3-δ (0.1≤x≤0.4) and BaFe0.9-yY0.1CoyO3-δ (0.05≤y≤0.15) were indexed using Pm3m space group. The unit cell parameters were refined using Rietveld full-profile analysis. Oxygen non-stoichiometry of these solid solutions was measured by means of thermogravimetric technique within the temperature range 298-1273 K in air.The work was supported under financial support from RFBR № 13-03-00958 and Ministry of Science and Education of Russian Federation within the limits of the Federal target program "Scientific and scienceeducational cadres of innovative Russia for 2009-2013"

Phase Equilibria in the YFeO3 – YCoO3 System in Air

Received: 14.03.2021. Revised: 10.04.2021. Accepted: 11.04.2021. Available online: 13.04.2021.YFe1-xСоxO3 solid solutions were prepared by glycerol-nitrate technique. The homogeneity range of solid solutions was studied within the temperature range 1173 – 1573 K. A continues series of solid solution below the decomposition temperature of YСоO3, which was shown to be equal to 1266 + 6 K, begins to narrow at higher temperatures and becomes equal to 0 ≤ x ≤ 0.1 at 1573 K. The phase diagram of the YFeO3 – YСoO3 system in the “T – composition” coordinates was divided into three fields. Similar to the parent ternary oxides, all single-phase YFe1-xСоxO3 solid solutions possess orthorhombically distorted perovskite structure (Pnma space group). Unusual behavior of orthorhombic distortions in YFe1-xСоxO3 with temperature was explained by probable changes in spin state of Co3+ ions.This work was supported in parts by the Ministry of Sci-ence and Higher Education of Russian Federation (№ АААА-А20-120061990010-7) and A.V.B. was supported with a stipend for young scientists and PhD students from the President of Russian Federation (№ SP-3689.2019.1)

Оцінювання технічного стану об’єктів інженерної інфраструктури меліоративних систем

Relevance of research. Existing problems with the use of existing capacities of hydraulic structures, especially farmer networks, have led to a significant reduction in the area of ​​irrigation and drainage systems, and, consequently, to reduce yields. This is a qualitative, objective assessment of the current state of reinforced concrete structures of hydraulic structures, which will contribute to the adoption of balanced, scientifically sound solutions for their restoration and modernization. In the article the modern state of the objects of engineering infrastructure of reclamation systems is investigated. Estimation of the technical condition of the overhead cover plates of the main pumping station of the Kakhovka Irrigation System, the Hydrotechnical Tunnel № 1 and the pumping stations of Inguletskoye, North-Rohachytsky irrigation systems, Irpin drainage and wetting, and also the number of other objects was completed. The purpose of the work is to study the reinforced concrete structures of the GTS meliorative systems, assess their technical condition and justify their restoration measures to improve operational reliability. Research methodology. Estimation of the current state of the objects of engineering infrastructure of land reclamation systems was carried out on the basis of analysis of technical documentation, visual assessment of the technical condition of structures, elements of structures, instrumental control of material properties and estimates. Conclusions.The systematization of typical damages and defects of concrete and reinforced concrete hydrotechnical structures is carried out. The obtained data became the basis for scientifically based selection and development of effective materials and technologies for restoration of operational properties and improvement of the strength of structures of reclamation systems. In this regard, the technology department for the repair of concrete and reinforced concrete structures with the use of polymeric and polymer-cement composite materials of different designation, which in a complex allow to solve the problems of restoration and reconstruction of the GTS from the emergency liquidation of active leaks, is investigated and developed in the department of exploitation of IWPLR NAAS in designs and ending with the restoration of the surface and the geometric shape of the structures.У статті досліджено сучасний стан об’єктів інженерної інфраструктури меліоративних систем. Проведено оцінювання технічного стану плит перекриття головної насосної станції Каховської зрошувальної системи, гідротехнічного тунелю № 1 та насосних станцій Інгулецької, Північно-Рогачицької зрошувальних систем, Ірпінської осушувально-зволожувальної системи та ряду інших об’єктів. Виконано систематизацію типових  пошкоджень  та дефектів бетонних та залізобетонних гідротехнічних споруд. Отримані дані стали основою для науково обгрунтованого вибору та розробки ефективних матеріалів та технологій для відновлення експлуатаційних властивостей та підвищення довговічності споруд меліоративних систем

SPECIFIC FEATURES OF PHASE EQUILIBRIUMS IN YFeO3 – YСoO3 SYSTEM IN AIR

YFe1-xCoxO3 phases have been prepared using a glycerol-nitrate technique at 1373 K in air. The X-ray diffraction (XRD) pattern for the single phases were refined by the Rietveld method within the orthorhombic structure (space group Pnma).Работа выполнена при поддержке совета по грантам Президента Российской Фе-дерации стипендии Президента Российской Федерации молодым ученым и аспирантам (Конкурс СП-2019) № СП-3689.2019.1«Получение новых перспективных матери-алов для электрохимических устройств на основе феррита иттрия-бария»

Synthesis and characterization of the oxygen-deficient perovskite BaFe0.9-xY0.1CoxO3-δ (0 ≤ x ≤ 0.15)

BaFe0.9-xY0.1CoxO3-δ (0 ≤ x ≤ 0.15) is shown to adopt the cubic perovskite structure at temperatures up to 1400 K in air. The oxygen vacancy concentration increases with both cobalt content and temperature, with BaFe0.75Y0.1Co0.15O2.35 being the most oxygen-deficient composition observed. At 700 K the conductivity is ∼2 S cm−1 across the whole composition range. Measurements of the Seebeck coefficient show that holes are the dominant carrier. The coefficient of thermal expansion is essentially constant above 800 K, but not at lower temperatures. Chemical reactivity tests, along with the coefficient of expansion, show that these perovskites would not be suitable electrodes for fuel cells with fluorite electrolytes but they might serve as permeable membranes in catalytic reactors. © 2016 Elsevier Lt

PHASE EQUILIBRIUM IN THE 1/2Dy2O3–SrO–1/2Fe2O3 SYSTEM AT 1100°C

The purpose of investigation is phase equilibria in the 1/2Dy2O3–SrO–1/2Fe2O3 system at 1100°C in air. Solid solution Dy1-xSrxFeO3 (0.0≤x≤0.1, x=0.9) and individual oxide Dy3Fe5O12 were found to form

STRUCTURE AND PHYSICOCHEMICAL PROPERTIES OF COMPLEX OXIDES Y1.2Ba1.8Fe3-XCoXO8+ Δ (X = 1.02, 1.05 AND 1.08)

The purpose of the study is to determine the structure, oxygen nonstoichiometry and phys-icochemical properties of complex oxides with the general formula Y1.2Ba1.8Fe3 - xCoxO8 + δ, where x = 1.02, 1.05, and 1.08.Работа выполнена при поддержке совета по грантам Президента Российской Фе-дерации стипендии Президента Российской Федерации молодым ученым и аспирантам (Конкурс СП-2019) № СП-3689.2019.1«Получение новых перспективных матери-алов для электрохимических устройств на основе феррита иттрия-бария»

SOLID SOLUTIONS BASED ON FERROCUPRATE OF BARIUM AND YTTRIUM

The samples were prepared using a glycerol–nitrate technique. All samples for the structural examination were quenched from 1273 K (cooling rate about 500 K/h) in air. Xray diffraction of powder samples was performed at room temperature using diffractometer Shimadzu XRD -7000 in Cu-K α radiation (λ=1,5418 Å). The structural parameters were refined by the Rietveld profile method using the Fullprof-2017 package

PHASE EQUILIBRIUM IN THE 1/2Dy2O3-SrO-CoO SYSTEM

The purpose of this study is to investigate the phase equilibria in the 1/2Dy2O3-SrO-CoO system at 1100°C in air. At present two binary oxides SrCoO3-δ, Sr3Co2O7-δ and individual oxide Dy0.14Sr0.86CoO3-δ were obtained

STRUCTURE OF OXIDE MATERIALS Y2Ba3Fe5-XCoXO13-Δ

Y2Ba3Fe5-xCoxO13-δ phases have been prepared using a glycerol-nitrate technique at 1373 K in air. The X-ray diffraction (XRD) pattern for the single phases were refined by the Rietveld method within the tetragonal structure (space group P4/mmm).Работа выполнена при поддержке совета по грантам Президента Российской Фе-дерации стипендии Президента Российской Федерации молодым ученым и аспирантам (Конкурс СП-2019) № СП-3689.2019.1«Получение новых перспективных материалов для электрохимических устройств на основе феррита иттрия-бария»