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采用固体电解质氧浓差电池研究了FeTiO_3-MgTiO_3固溶体系的氧分压和活度。选用Fe/FeO为参比极,测得其氧分压,并求出非化学计量FeO的标准自由焓ΔG°FeO=-259030+60.25T(J·mol~(-1))。测定了固溶体系不同组成,在900—1200℃区间的氧分压和FeO的活度。其结果表明,二者均随温度的升高而增加。将数据处理后,得到生成复合氧化物FeTiO_3的标准生成自由焓,ΔG°FeTio_3=-40470+19.75T(J·mol~(-1))以及固溶体的组元活度与组成的关系图。

The oxygen partial pressure and activity of FeTiO_3-MgTiO_3 solid-solution system were studied by means of oxygen concentration cell with the solid electrolyte. Taken Fe/FeO as reference electrode, the oxygen partial pressure was measured, and standard free enthalpy of formation of non-stoichiometric FeO (w/istite) was obtained as ΔG_(FeO)~0=-259030+60.25T (J·mol~(-1)). Furthermore, the oxygen partial pressure and wustite activity of the various compositions of the solid-solution system were measured at the temperature range of 900—1200℃. The results show that both values increase with the increase of temperature. The standard free enthalpy of formation of complex oxide FeTiO_3, ΔG_(FeTiO_3)~0=-40470+19.75T (J·mol~(-1)) and the activity-composition relation of this solid-solution series were obtained.