Determination of the P e value of 5 wt-% calcia stabilised hafnia solid electrolyte at high temperatures

Abstract

In the context of the measurement of oxygen activities at high temperatures in ironmaking and steelmaking, the P _e value of a 5 wt-% calcia stabilised hafnia long tube was determined by the coulometric titration technique at high temperature. According to values obtained in this paper, the P _e value could be expressed as: logP _e = (–66 468/ T) + 17.97 for temperatures between 1400 and 1620°C. This is similar to values published in the literature. It was also discovered that the chemical composition of the solid electrolyte as well as the oxygen partial pressure inside the hafnia tube has an influence on the P _e value. Therefore, it is necessary to measure the P _e value of solid electrolytes prior to their use in steelmaking.