Galvanic-cell investigations with a CaF 2 solid electrolyte at elevated temperatures

Abstract

Recent results from our laboratory indicate that CaF 2 can be used to measure oxygen and sulfur chemical potentials in the temperature range of 500–900°C. A theoretical explanation of the manner in which the CaF 2 electrolyte functions as either an oxygen or a sulfur sensor is presented. It is concluded that CaF 2 is a useful electrolyte for the measurement of extremely low oxygen chemical potentials, possibly even in regions where zirconia-based and thoria-based oxide electrolytes exhibit n-type electronic conductivity. The CaF 2 electrolyte is also suitable for the measurement of sulfur chemical potentials in solids and gas mixtures.