IONIC-CONDUCTION BEHAVIOR OF MULLITE (3AL2O3.2SIO2) AT 1400-DEGREES-CTO 1600-DEGREES-C

The present work deals with mullite (Al2O3.2SiO2) as a potential mater ial for application as solid electrolyte in high-temperature electroch emical devices. The structure and preparation of mullite and the desig n of mullite-based oxygen sensors are described. The predominantly ion ic conduction of mullite is characterized by means of the parameter P( e') (t(ion) = 0.5) of electronic conductivity and the temperature depe ndence of the ionic transference number t(ion). It is confirmed that m ullite features ionic conductivity superior to that of the usual CaO-s tabilized ZrO2 solid electrolytes at temperature from 1400 to 1600-deg rees-C.