Gibbs’ energy of formation of YBa2Cu3O7-x (tetragonal)

Azad, AM and Jacob, KT and Sreedharan, OM (1991) Gibbs’ energy of formation of YBa2Cu3O7-x (tetragonal). In: Bulletin of Materials Science, 14 (4). pp. 983-987.

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Abstract

The high temperature ceramic oxide superconductor YBa2Cu3O7-x (1–2–3 compound) is generally synthesized in an oxygen-rich environment. Hence any method for determining its thermodynamic stability should operate at a high oxygen partial pressure. A solid-state cell incorporating CaF2 as the electrolyte and functioning under pure oxygen at a pressure of 1·01 × 105 Pa has been employed for the determination of the Gibbs’ energy of formation of the 1–2–3 compound. The configuration of the galvanic cell can be represented by: Pt, O2, YBa2Cu3O7−x , Y2BaCuO5, CuO, BaF2/CaF2/BaF2, BaZrO3, ZrO2, O2, Pt. Using the values of the standard Gibbs’ energy of formation of the compounds BaZrO3 and Y2BaCuO5 from the literature, the Gibbs’ energy of formation of the 1–2–3 compound from the constituent binary oxides has been computed at different temperatures. The value ofx at each temperature is determined by the oxygen partial pressure. At 1023 K for O content of 6·5 the Gibbs’ energy of formation of the 1–2–3 compound is −261·7 kJ mol−1.

Item Type:	Journal Article
Publication:	Bulletin of Materials Science
Publisher:	Indian Academy of Sciences
Additional Information:	Copyright of this article belongs to Indian Academy of Sciences.
Keywords:	Gibbs’ energy;oxygen partial pressure;free energy;stability
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	09 Dec 2011 09:38
Last Modified:	09 Dec 2011 09:38
URI:	http://eprints.iisc.ac.in/id/eprint/42671

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