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Phase equilibria in the 1/2Y 2 O 3 -SrO-1/2Fe 2 O 3 system were systematically studied at 1373 K in air. The homogeneity ranges and crystal structure of the solid solutions Sr 1−x Y x FeO 3−δ with 0.875 ≤ x ≤ 1 (sp. gr. Pnma) and 0.05 ≤ x ≤ 0.25 (sp. gr. Pm3 m) and Sr 3−z Y z Fe 2 O 7−δ with 0 ≤ z ≤ 0.25 (sp. gr. I4/mmm) were determined by X-ray diffraction analysis of quenched samples. The structural parameters of the single-phase oxides were refined by the Rietveld profile method. The isothermal-isobaric phase diagram for the 1/2Y 2 O 3 -SrO-1/2Fe 2 O 3 system at 1373 K in air is presented. The changes of oxygen content in the solid solutions Sr 1−x Y x FeO 3−δ (0.05 ≤ x ≤ 0.25) and Sr 3−z Y z Fe 2 O 7−δ with 0 ≤ z ≤ 0.25 vs temperature in air were determined by the thermogravimetric analysis. Oxygen content was also calculated from the iodometric titration results. The gradual substitution of strontium by yttrium in Sr 1−x Y x FeO 3−δ (0.05 ≤ x ≤ 0.25) leads to a decrease in the oxygen content and the mean oxidation state of iron. The average thermal expansion coefficients for Sr 1−x Y x FeO 3−δ (0.875 ≤ x ≤ 1 and 0.05 ≤ x ≤ 0.25) and Sr 3−z Y z Fe 2 O 7−δ (0 ≤ z ≤ 0.25) were calculated within the temperature range 298-1373 K in air. K E Y W O R D S crystal structure, oxygen content, phase diagram, solid solution, thermal expansion, total electric conductivity, X-ray diffraction

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Polycrystalline “112” ordered oxygen deficient double perovskites YBaCo2−xMexO5+δ (Me = Fe, Cu, Ni) were synthesized by a glycerol-nitrate route with 0.0 ≤ x ≤ 0.7 for Me = Fe, 0.0 ≤ x ≤ 0.6 for Me = Cu and x = 0.1 for Me = Ni.

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Phase equilibria and thermodynamic properties of oxide systems on the basis of rare earth, alkaline earth and 3d-transition (Mn, Fe, Co) metals. A short overview of.Review is dedicated studies of phase equilibria in the systems based on rare earth elements and 3d transition metals. It's highlighted several structural families of these compounds and is shown that many were found interesting properties for practical application, such as high conductivity up to the superconducting state, magnetic properties, catalytic activity of the processes of afterburning of exhaust gases, the high mobility in the oxygen sublattice and more.Keywords: phase equilibrium; manganites; isobaric-isothermal diagrams; solid solutions © Cherepanov V. A., Gavrilova L. Ya., Volkova N. E., Urusova A. S., Aksenova T. V., Kiselev E., 2015 IntroductionThe studies of phase equilibria in the systems based on rare earth elements and 3d transition metals and thermodynamic parameters of the oxide phases formed in these systems was initiated by Vladimir Mikhailovich Zhukovsky in 1977 under the direct supervision of Alexander Nikolaevich Petrov, as the development of contractual issues, conducted with an experienced company GIREDMET. The works on the study of the system Sm-Co-O and properties of oxide phases formed in system were then extended to other rare earth elements (REE) [1][2][3][4][5][6][7][8] and 3d transition metals [9][10][11][12][13]. A characteristic feature of these systems is the formation of oxide phases with perovskite structure AVO 3 and related. The partial substitution of rare earth elements in alkaline earth metals (AEM) leads to significant change of properties and they found a wide range of interesting for practical applications of the properties such as high conductivity up to the superconducting state, magnetic properties, catalytic activity of the processes of afterburning of exhaust gases and a variety of redox reactions, high mobility in the oxygen sublattice and more. In addition, partial substitution in the A-sublattice under constant 3d-cation in the systems Ln-T-O allows to stabilize the structure, which Cherepanov V. A., Gavrilova L. Ya., Volkova N. E., Urusova A. S., Aksenova T. V., Kiselev E. in the given conditions (temperature and oxygen pressure) are thermodynamically unstable. Therefore, further development of investigations of phase equilibria and thermodynamic stability of complex oxides were targeting the systems Ln-M-T-O (where Ln = REE, M = Ca, Sr, Ba; T = Mn, Fe, Co, Ni, Cu). When a certain percentage of similarity (in all possible formation of a phase with perovskite structure LnTO 3±d ) these systems still have a noticeable and distinctive features depending on the nature of the components. Phase equilibrium in systems with T = MnThe significant difference of perovskite phases in the manganese-containing systems Ln-Mn-O is that the oxygen content in them exceeds the stoichiometric air LnMnO 3+d . In fact, the oxygen sublattice is complete and the non-stoichiometry is realized by vacancy disordering ...