Phase equilibria in the La-Ba-Co-O system

Journal Article · Thu Apr 01 04:00:00 EST 1999 · Materials Research Bulletin

DOI:https://doi.org/10.1016/S0025-5408(99)00092-6· OSTI ID:684415

Cherepanov, V A; Gavrilova, L Y; Filonova, E A; Trifonova, M V ^[1]; Voronin, V I ^[2]

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1. Ural State Univ., Ekaterinburg (Russian Federation). Dept. of Chemistry
2. Russian Academy of Sciences, Ekaterinburg (Russian Federation). Inst. for Metal Physics

Phase equilibria in the La-Ba-Co-O system were studied at 1,100 C in air. The existence of oxide phases LaCoO{sub 3}, BaCoO{sub 3{minus}y}, Ba{sub 2}CoO{sub 4}, and La{sub 2}BaO{sub 4} in quasibinary systems in air at 1,100 C was found, in agreement with previous data. Two types of solid solutions were found in the quasiternary system: La{sub 1{minus}x}Ba{sub x}CoO{sub 3{minus}{delta}} and (La{sub 1{minus}z}Ba{sub z}){sub x}CoO{sub 4}. The homogeneity range of La{sub 1{minus}x}Ba{sub x}CoO{sub 3{minus}{delta}} was found to be 0 {le} x {le} 0.8. As the content of alkali-earth metal (x) increased, a rhombohedral distortion of La{sub 1{minus}x}Ba{sub x}CoO{sub 3{minus}{delta}} decreased; La{sub 0.55}Ba{sub 0.45}CoO{sub 3{minus}{delta}} had an ideal cubic structure. The composition of single phase samples of (La{sub 1{minus}z}Ba{sub z}){sub 2}CoO{sub 4} composition was obtained for z = 0.300, 0.325, 0.350, and 0.375. These samples had the tetragonal K{sub 2}NiF{sub 4}-type structure.

• OSTI ID: 684415
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 6 Vol. 34; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
CHEMICAL COMPOSITION
COBALT OXIDES
LANTHANUM OXIDES
PHASE STUDIES
SOLID SOLUTIONS
TEMPERATURE RANGE 1000-4000 K