ELECTRICAL-PROPERTIES OF ZRO2-TIO2-Y2O3 SYSTEM

Electrical properties of the mixed conductor, ZrO2-TiO2-Y2O3 system were measured in the temperature range from 400 to 1400-degrees-C. The oxygen partial pressure dependence of the electrical conductivity was measured in the oxygen partial pressure range from 0.21 to 1 X 10(-24) atm controlled by H2-CO2 MiXed gas. The total electrical conductivity decreases with increasing titania concentration due to the block of oxygen ions by titanium ions. With no sintering aids like silica and alumina, both bulk and grain boundary conductivity decrease. The electronic conduction is negligibly small and the ionic conduction is dominant in high oxygen partial pressure range. The electronic conductivity appears at low oxygen partial pressure: lower than 10(-17) atm and at 1000-degrees-C in YSZ containing 10 mol% titania. The electronic conduction of this system is n-type and is due to small polaron hopping mechanism caused by electrons hopping between Ti3+ and Ti4+ ions.