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Defect Chemistry and Phase Equilibria of (La1-xCax)FeO3-δ Thermodynamic Modeling.
- Source :
- Journal of The Electrochemical Society; 2013, Vol. 160 Issue 10, pF1103-F1108, 6p
- Publication Year :
- 2013
-
Abstract
- Thermodynamics of defects in the (La<subscript>x</subscript>Ca<subscript>1-x</subscript>)FeO<subscript>3-δ</subscript> perovskite is modeled by means of the CALPHAD approach. In this phase, the A-sites are occupied by La<superscript>+3</superscript> and Ca<superscript>+2</superscript>, and Fe in the B-site is known to exist in +2, +3, and +4 oxidation states depending on the oxygen vacancy concentration. Therefore, the ionic sublattice model: (La<superscript>+3</superscript>, Ca<superscript>+2</superscript>)(Fe<superscript>+2</superscript>, Fe<superscript>+3</superscript>, Fe<superscript>+4</superscript>)(O<superscript>-2</superscript>, Va)<subscript>3</subscript> is used to describe the phase, and the model parameters are evaluated from experimental oxygen nonstoichiometry and phase equilibria data. With the Fe<superscript>+2</superscript> and Fe<superscript>+4</superscript> treated as the major species in the B-site, the calculated phase diagrams are in good agreement with the experimentally reported phase equilibria data. The concentration of various defects in (La<subscript>x</subscript>Ca<subscript>1-x</subscript>)FeO<subscript>3-δ</subscript> as a function of oxygen partial pressure and temperature are calculated at different concentrations of Ca. At high oxygen partial pressures, Fe<superscript>+4</superscript> is predicted to be dominant while Fe<superscript>+2</superscript> is dominant at low oxygen partial pressures. [ABSTRACT FROM AUTHOR]
- Subjects :
- SURFACE defects
THERMODYNAMICS
PHASE equilibrium
FUEL cells
PEROVSKITE
Subjects
Details
- Language :
- English
- ISSN :
- 00134651
- Volume :
- 160
- Issue :
- 10
- Database :
- Supplemental Index
- Journal :
- Journal of The Electrochemical Society
- Publication Type :
- Academic Journal
- Accession number :
- 91721489
- Full Text :
- https://doi.org/10.1149/2.105309jes