Ion-exchange equilibria between (Mn, Co)O solid solution and (Mn, Co) Cr2O4 and (Mn, Co) Al2O4 spinel solid solutions at 1100°C

Jacob, K. T. ; Fitzner, K. (1977) Ion-exchange equilibria between (Mn, Co)O solid solution and (Mn, Co) Cr2O4 and (Mn, Co) Al2O4 spinel solid solutions at 1100°C Journal of Materials Science, 12 (3). pp. 481-488. ISSN 0022-2461

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Official URL: http://www.springerlink.com/content/jmg83v33n06285...

Related URL: http://dx.doi.org/10.1007/BF00540270

Abstract

The compositions of the (Mn,Co)O solid solution with rock salt structure in equilibrium with (Mn,Co)Cr2O4 and (Mn,Co)Al2O4 spinel solid solutions have been determined by X-ray diffraction measurements at 1100° C and an oxygen partial pressure of 10-10 atm. The ion exchange equilibria are quantitatively analysed, using values for activities in the (Mn,Co)O solid solution available in the literature, in order to obtain activities in the spinel solid solutions. The MnAl2O4-CoAl2O4 solid solution exhibits negative deviations from Raoult's law, consistent with the estimated cation disorder in the solid solution, while the MnCr2O4-CoCr2O4 solid solution shows slightly positive deviations. The difference in the Gibbs free energy of formation of the two pure chromites and aluminates derived from the results of this study are in good agreement with recent results obtained from solid oxide galvanic cells and gas-equilibrium techniques.

Item Type:Article
Source:Copyright of this article belongs to Springer-Verlag.
ID Code:12916
Deposited On:11 Nov 2010 08:26
Last Modified:16 May 2016 22:10

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