Solid state equilibria in the Ba-Cu-O system

Journal Article · Sun May 01 04:00:00 EDT 1994 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1006/jssc.1994.1134· OSTI ID:6769889

Voronin, G F; Degterov, S A ^[1]

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1. Moscow State Univ. (Russian Federation)

Thermodynamic modeling is performed for the Ba-Cu-O system, which is essential to a good understanding of phase and chemical equilibria in the Y-Ba-Cu-O and some other oxide systems containing high-temperature superconductors. A self-consistent set of thermodynamic functions of the phases BaO[sub 2], BaCu[sub 2]O[sub 2], BaCuO[sub 2], Ba[sub 2]Cu[sub 3]O[sub 5+y], and Ba[sub 2]CuO[sub 3+q] is obtained. A variety of phase equilibria in the Ba-Cu-O system are calculated for a wide range of oxygen pressures and temperatures. The present thermodynamic data can be readily used for computing the phase equilibria and conditions for thermodynamic stability of oxide superconductors. It is detected that both BaCuO[sub 2] and Ba[sub 2]CuO[sub 3+q] have two stability boundaries, one at low temperatures and low oxygen pressures. Critical analysis of phase equilibria in the Ba-Cu-O system makes it possible to explain a number of conflicting results encountered in the literature. These contradictions arise from solid state reactions between phases, which may be very slow due to kinetic problems.

• OSTI ID: 6769889
• Journal Information: Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Vol. 110:1; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
COPPER COMPOUNDS
CUPRATES
EQUILIBRIUM
HIGH-TC SUPERCONDUCTORS
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
STABILITY
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS