ELECTRICAL-PROPERTIES OF THE ZRO2-CEO2 SYSTEM

The electrical properties of ZrO2-CeO2 solid solutions are investigate d in detail as functions of the temperature between 200 and 1000 degre es C and of the ceria molar fraction between 16 and 100% (pure CeO2). The samples are studied by combining impedance spectroscopy, ionic tra nsport number and thermoelectric power measurements so as to define th e role and the contribution of hole and electron carriers to the condu ctivity mechanism. In particular, the transition from p- to n-type con ductivity of undoped CeO2 at 750 degrees C is clearly demonstrated. Th e conductivity dependence on the oxygen partial pressure is also studi ed in the ZrO2-80 mol% CeO2 composition that exhibits the highest elec tronic conductivity.