Abstract
The electromotive force (e. m. f.) of mullite ceramics with a density of 97.9% T. D. as a solid electrolyte for oxygen concentration cell was measured between 873 and 1573K in the oxygen pressure range of 1.0×103.5 to 1.0×10-2Pa. The measured e. m. f. indicates that the ionic transport number (ti) of oxygen is higher than 0.8 above 1273K at oxygen pressures above 1.0×102.5Pa. The ti decreased with decreasing oxygen pressure and was not sensitive to oxygen pressure below 1073K. Above results were discussed in relation to the electronic conduction due to thermal decomposition of lattice oxygen of mullite in a reduced atmosphere.
