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Phase Equilibria, Crystal Structure, and Properties of Intermediate Oxides in the Sm 2 O 3 –SrO–CoO System
Author(s) -
Volkova Nadezhda E.,
Maklakova Anastasia V.,
Gavrilova Ludmila Ya.,
Cherepanov Vladimir A.
Publication year - 2017
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201700321
Subject(s) - samarium , chemistry , tetragonal crystal system , strontium , cobaltite , analytical chemistry (journal) , crystallography , crystal structure , rietveld refinement , phase (matter) , isothermal process , solid solution , phase diagram , inorganic chemistry , thermodynamics , physics , organic chemistry , chromatography
The phase equilibria in the 1 / 2 Sm 2 O 3 –SrO–CoO system were systematically studied at 1100 °C in air. Single‐phase Sr 1– x Sm x CoO 3– δ and Sr 2– y Sm y CoO 4+ δ solid solutions were obtained within the ranges of 0.05 ≤ x ≤ 0.50 and 0.9 ≤ y ≤ 1.3, respectively. XRD patterns of the single‐phase samples were refined by the Rietveld method within the tetragonal structure (space group I 4/ mmm ). Gradual substitution of strontium by samarium leads to a decrease of the unit‐cell parameters and the unit‐cell volume that can be explained by the size factor. An introduction of samarium into strontium cobaltite increases the oxygen content in Sr 1– x Sm x CoO 3– δ . The variation of the electrical conductivity, Seebeck coefficient, and thermal expansion of Sr 1– x Sm x CoO 3– δ and Sr 2– y Sm y CoO 4+ δ oxides vs. temperature were measured in air. The chemical reactivity of Sr 1– x Sm x CoO 3– δ and Sr 2– y Sm y CoO 4+ δ , in contact with the solid electrolyte materials Ce 0.8 Sm 0.2 O 2 and Zr 0.85 Y 0.15 O 2 , was examined. The projection of the isothermal–isobaric phase diagram (1100 °C, air) to the compositional triangle 1 / 2 Sm 2 O 3 –SrO–CoO has been constructed.