Thermodynamics of NdRhO3 and phase relations in the system Nd-Rh-O

Jacob, KT and Gupta, Preeti and Han, Donglin and Uda, Tetsuya (2013) Thermodynamics of NdRhO3 and phase relations in the system Nd-Rh-O. In: CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY, 43 . pp. 71-79.

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Abstract

Phase equilibrium experiments indicate that NdRhO3 is the only ternary oxide in the system Nd-Rh-O at 1273 K; it has orthorhombically-distorted perovskite structure. By employing a solid-state electrochemical cell incorporating calcia-stabilized zirconia as the electrolyte, thermodynamic properties of NdRhO3 are determined. The standard Gibbs energy of formation of NdRhO3 from its component binary oxides in the temperature ranges from 900 to 1300 K can be expressed as: 1/2Rh(2)O(3) (ortho)+1/2Nd(2)O(3)(hex)=NdRhO3(ortho), Delta(f(o,x))G(0)/J mol(-1)( +/- 197) = - 66256+5.64 (T/K). The decomposition temperature of NdRhO3 computed from extrapolated thermodynamic data is 1803 (+/- 4) K in pure oxygen and 1692 (+/- 4) K in air at standard pressure. Oxygen partial pressure-composition diagram and three-dimensional chemical potential diagram at 1273 K are developed from thermodynamic data obtained in this study and auxiliary information from the literature. Equilibrium temperature-composition phase diagrams at constant oxygen partial pressures are also constructed. (C) 2013 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Additional Information:	copyright for this article belongs to PERGAMON-ELSEVIER SCIENCE LTD,ENGLAND
Keywords:	Phase equilibria; NdRhO3; Nd-Rh-O system; Gibbs energy; Enthalpy
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	07 Jan 2014 05:41
Last Modified:	07 Jan 2014 05:42
URI:	http://eprints.iisc.ac.in/id/eprint/48144

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