Determination of electronic conductivity limits of mullite and ZrO2-9 mol% MgO solid electrolytes

Abstract

A coulometric titration technique was used for the determination of the parameterPϑ, defined as the oxygen partial pressure at which the ionic conductivity and n-type electronic conductivity of the electrolyte are equal, for mullite and 9 mol% MgO stabilized zirconia electrolytes in the temperature range 1674–1921 K. The results ofPϑ for mullite and ZrO2-9 mol% MgO were log(Pϑ/101 325 Pa)=54.32−137000/T and log (Pϑ/101 325 Pa)=27.16–75500/T, respectively. The results for low oxygen activities in liquid iron are discussed on the basis of the present results forPϑ values.