Electrical conductivity of the system ZrO 2-Er 2O 3

Abstract

ZrO 2-Er 2O 3, solid solutions containing 10, 15, and 20 mol% Er 2O 3 were prepared with spectroscopically pure ZrO 2; and Er 2O 3 polycrystalline powder. All systems were found to have the cubic fluorite structure by X-ray diffraction techniques. Electrical conductivities were measured as a function of temperature from 400 to 1000°C and of oxygen partial pressure from 10 −6 to 2 × 10 −1 atm. The defect structure, type of semiconductor behavior and the electrical conduction mechanism were deduced from these results. The temperature dependence of the electrical conductivities shows different behavior in the low- and high-temperature regions. The activation energies increase with decreasing oxygen pressure and increasing dopant level. The dependence of the conductivity on the oxygen partial pressure (σ∞ P O 2 − 1 n ) are 1 n = 0 and n = 40−4 in the low- and high-temperature regions, respectively. The n values in the high-temperature region decrease with increasing temperature. From the variation of the n values with temperature, mixed ionic and electronic conduction is suggested. Oxygen ion conduction is also suggested in the low-temperature region from the oxygen ion mobility.