亜鉛-鉄-酸素系に関する熱力学的研究

抄録

The Zn-Fe-O system can be divided thermodynamically into three regions: (i) Fe-Zn-ZnO-FeO system, (ii) FeO-ZnO-ZnFe₂O₄-Fe₃O₄ system and (iii) Fe₃O₄-ZnFe₂O₄-Fe₂O₃ system. Phase relations in each system have been studied at 1200 K by equilibrating synthetic samples in evacuated sealed quartz tubes. The results indicate that the phase relations at 1200 K are almost the same as that at 1100 K, while the mutual solid solubilities at 1200 K between ZnO and FeO are slightly larger than that at 1100 K. On the basis of the results and the previous data concerning the EMF using a stabilized zirconium oxide solid electrolyte, the equilibrium partial pressures of oxygen, −logp_O2(=−log(P_O2⁄P^\ominus)), at 1200 K were thus estimated as follows: 20-16 for region (i), 14-12 for region (ii) and 6-3 for region (iii), respectively.
The activities of the components in Fe-Zn, FeO-ZnO and Fe₃O₄-ZnFe₂O₄ systems were then obtained by applying the Gibbs-Duhem relation in each region.