Thermodynamics of GdMnO3 and GdMn2O5 phases determined by the EMF method

Pawlas-Foryst, E and Jacob, KT and Fitzner, K (2006) Thermodynamics of GdMnO3 and GdMn2O5 phases determined by the EMF method. In: Archives Of Metallurgy And Materials, 51 (3). pp. 481-488.

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Abstract

Using solid oxide galvanic cells of the type: MnO + Gd2O3 + GdMnO3/O-2/Ni + NiO and Mn3O4 + GdMnO3 + GdMn2O5/O-2/air the equilibrium oxygen pressure for the following reactions :MnO + 1/2Gd(2)O(3) + 1/4O(2) = GdMnO3 1/3Mn(3)O(4) + GdMnO3 + 1/3O(2) = GdMn2O5 was determined in the temperature range from 1073 to 1450 K. From the determined equilibrium oxygen partial pressure the corresponding G i b b s free energy change for these reactions was derived: Delta G(f,GdMnO3)(0) (+/- 425J) 132721(+/ - 2240) +51.91(+/ - 0.81)T Delta G(f,GdMn2O5)(0)(+/- 670J) 121858(+/ - 6176) + 79.52(+/ - 4.83)T From these data, standard G i b b s energies, enthalpies and entropies of formation of GdMnO3 and GdMn2O5 from component oxides and from the elements are derived. Thermodynamic data tables for the two ternary phases are compiled from 298.15 to 1400 K.

Item Type:	Journal Article
Publication:	Archives Of Metallurgy And Materials
Publisher:	Institute of Metallurgy and Meterials Science
Additional Information:	copyright of this article belongs to Institute of Metallurgy and Materials Science.
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	01 Sep 2010 08:25
Last Modified:	19 Sep 2010 06:12
URI:	http://eprints.iisc.ac.in/id/eprint/30761

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