Electrochemical determination of thermodynamic properties of DyRhO3 and phase relations in the system Dy-Rh-O

Jacob, Kallarackel T and Gupta, Preeti (2013) Electrochemical determination of thermodynamic properties of DyRhO3 and phase relations in the system Dy-Rh-O. In: JOURNAL OF SOLID STATE ELECTROCHEMISTRY, 17 (3). pp. 607-615.

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Abstract

Thermodynamic properties of Dysprosium rhodite (DyRhO3) are measured in the temperature range from 900 to 1,300 K using a solid-state electrochemical cell incorporating yttria-stabilized zirconia as the electrolyte. The standard Gibbs free energy of formation of DyRhO3 with O-type perovskite structure from its components binary oxides, Dysprosia with C-rare earth structure and beta-Rh2O3 with orthorhombic structure, can be represented by the equation: Delta G(f(OX))(O) (+/- 182)/J mol(-1) = -52710+3.821(T/K). By using the thermodynamic data for DyRhO3 from experiment and auxiliary data for other phases from the literature, the phase relations in the system Dy-Rh-O are computed. Thermodynamic data for intermetallic phases in the binary system Dy-Rh, required for constructing the chemical potential diagrams, are evaluated using calorimetric data available in the literature for three intermetallics and Miedema's model, consistent with the phase diagram. The results are presented in the form of Gibbs triangle, oxygen potential-composition diagram, and three-dimensional chemical potential diagram at 1,273 K. Temperature-composition diagrams at constant oxygen partial pressures are also developed. The decomposition temperature of DyRhO3 is 1,732 (+/- 2.5) K in pure oxygen and 1,624 (+/- 2.5) K and in air at standard pressure.

Item Type:	Journal Article
Publication:	JOURNAL OF SOLID STATE ELECTROCHEMISTRY
Publisher:	SPRINGER
Additional Information:	Copyright for this article belongs to SPRINGER, NEW YORK,
Keywords:	Solid-state electrochemical cell; DyRhO3;3-D chemical potential diagram;O-type perovskite structure;Dy-Rh binary system;Oxygen potential
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	14 Mar 2013 09:49
Last Modified:	14 Mar 2013 09:49
URI:	http://eprints.iisc.ac.in/id/eprint/46059

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