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The CaO-SrO-CuO-O-2 system: Phase equilibria and thermodynamic properties at 1123 K

Jacob, KT and Raj, Markondeya P and Waseda, Y (1995) The CaO-SrO-CuO-O-2 system: Phase equilibria and thermodynamic properties at 1123 K. In: Journal of Phase Equilibria, 16 (2). pp. 113-120.

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Abstract

Phase relationships in the CaO-SrO-CuO system in pure oxygen at 1.01 x 10(5) Pa pressure were determined by equilibrating different compositions at 1123 K for similar to 120 h and analyzing the phases present in the quenched samples using X-ray diffraction (XRD), optical and scanning electron microscopy, and energy dispersive analysis of X-rays (EDAX). Four solid solution series were observed in the system, The CawSr1-wO monoxide solid solution with rock-salt structure was found to exhibit an asymmetric miscibility gap, The mixing properties of the monoxide system were deduced using a subregular solution model, For the (CaxSr1-x)(2)CuO3 series, a complete solid solution range with orthorhombic space group Immm was obtained. Calcium substituted for strontium up to 68 at. % in SrCuO2+delta and 51.5 at. % in Sr14Cu24O41-delta. The tie lines between the solid solutions were determined accurately, The activity-composition relations in (CaxSr1-x)(2)CuO3, CaySr1-yCuO2+delta, and (Ca2Sr1-z)(14)Cu24O41-delta solid solutions were determined from experimental tie lines. Activities in the (CaxSr1-x)(2)CuO3 and CaySr1-yCuO2+delta series were close to the predictions of the Temkin model, The behavior of the (CazSr1-(z))(14)Cu24O41-delta solid solution was more complex, with the activity of SrCu(24/14)O-(41-delta/14) exhibiting both positive and negative deviations from ideality. Gibbs energy of formation of the CaCuO2+delta metastable phase at 1123 K was deduced from an analysis of the phase diagram.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to ASM International.
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited: 26 May 2011 09:48
Last Modified: 26 May 2011 09:48
URI: http://eprints.iisc.ernet.in/id/eprint/37955

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