Oxide Ion Titrations in Molten NaCI with the Zirconia Electrode

Stabilized zirconia electrolytes can be used to titrate O 2- into and out of molten NaC1. Relations between the oxide activity in the melt and the charge passed through the ceramic have been derived and verified. The technique is applicable to the purification of melts and the determination of oxide solu-bil ity products. Zirconia stabilized with several percent CaO, MgO, or Y20 ~ is finding increasing use in a variety of applications at high temperatures. All of these de-pend on the fact that charge transport hrough this material occurs by migration of oxide (02- ) ions (1). Electrochemical applications may be divided into equil ibrium methods in which the stabilized ZrO2 (SZ) is used as part of an indicator electrode, and nonequi l ibr ium ethods in which a sensible amoun