Ling Wang, Huizhu Zhou, Yanruo Hong, and Girish M Kale, Electrochemical determination of Gibbs free energy of formation of magnesium ferrite, J. Univ. Sci. Technol. Beijing, 14(2007), No. 4, pp. 361-364. https://doi.org/10.1016/S1005-8850(07)60071-1
Cite this article as:
Ling Wang, Huizhu Zhou, Yanruo Hong, and Girish M Kale, Electrochemical determination of Gibbs free energy of formation of magnesium ferrite, J. Univ. Sci. Technol. Beijing, 14(2007), No. 4, pp. 361-364. https://doi.org/10.1016/S1005-8850(07)60071-1
Ling Wang, Huizhu Zhou, Yanruo Hong, and Girish M Kale, Electrochemical determination of Gibbs free energy of formation of magnesium ferrite, J. Univ. Sci. Technol. Beijing, 14(2007), No. 4, pp. 361-364. https://doi.org/10.1016/S1005-8850(07)60071-1
Citation:
Ling Wang, Huizhu Zhou, Yanruo Hong, and Girish M Kale, Electrochemical determination of Gibbs free energy of formation of magnesium ferrite, J. Univ. Sci. Technol. Beijing, 14(2007), No. 4, pp. 361-364. https://doi.org/10.1016/S1005-8850(07)60071-1
The standard Gibbs free energy of formation of magnesium ferrite was determined by means of two types of solid state electrochemical cells: one using MgZr4(PO4)6 (MZP) as the solid electrolyte and the other using CaF2 as the solid electrolyte. The first cell was operated in the range of 950 to 1100 K. The second cell was operated in the range of 1125 to 1200 K. The reversibility of the cell EMFs was confirmed by microcoulometric titration. The Gibbs energy changes of magnesium ferrite relative to component oxides were calculated based on EMF measurements and are given by following expressions, respectively: △$G_Ⅰ^{{\rm{\rlap{-} o}}}$ = -3579-15 T (J/mol) and △$G_Ⅱ^{{\rm{\rlap{-} o}}}$ =6258-24.3 T (J/mol). The results obtained from two different cells are consistent with each other. The results also are in agreement with Rao's and Tretjakov's data in the measured temperature range. When the Gibbs free energies of formation of MgO and Fe203 were substituted in the reaction, the Gibbs free energies of formation of MgFe204 was obtained in two temperature ranges and the for mations are shown as follows: △$G_{Ⅰ\;{\rm{Formation}}}^{{\rm{\rlap{-} o}}}$ =-1427394+360.5 T (J/mol) and △$G_{Ⅱ\;{\rm{Formation}}}^{{\rm{\rlap{-} o}}}$ =-1417557+351.2 T (J/mol).
The standard Gibbs free energy of formation of magnesium ferrite was determined by means of two types of solid state electrochemical cells: one using MgZr4(PO4)6 (MZP) as the solid electrolyte and the other using CaF2 as the solid electrolyte. The first cell was operated in the range of 950 to 1100 K. The second cell was operated in the range of 1125 to 1200 K. The reversibility of the cell EMFs was confirmed by microcoulometric titration. The Gibbs energy changes of magnesium ferrite relative to component oxides were calculated based on EMF measurements and are given by following expressions, respectively: △$G_Ⅰ^{{\rm{\rlap{-} o}}}$ = -3579-15 T (J/mol) and △$G_Ⅱ^{{\rm{\rlap{-} o}}}$ =6258-24.3 T (J/mol). The results obtained from two different cells are consistent with each other. The results also are in agreement with Rao's and Tretjakov's data in the measured temperature range. When the Gibbs free energies of formation of MgO and Fe203 were substituted in the reaction, the Gibbs free energies of formation of MgFe204 was obtained in two temperature ranges and the for mations are shown as follows: △$G_{Ⅰ\;{\rm{Formation}}}^{{\rm{\rlap{-} o}}}$ =-1427394+360.5 T (J/mol) and △$G_{Ⅱ\;{\rm{Formation}}}^{{\rm{\rlap{-} o}}}$ =-1417557+351.2 T (J/mol).