Microstructure and Electrical Conductivity of Yttria Stabilized Zirconia (8Y-CSZ) Containing Small NiO Addition

Abstract

In this study, the effect of addition in small contents of NiO on microstructure and electrical conductivity properties of 8 mol% yittria stabilized cubic zirconia (8Y-CSZ) were investigated. Specimens were produced by colloidal processing from 1 wt% NiO and 99 wt% 8Y-CSZ powders. Specimens were pressurelless sintered at 1,400 o C for 10 h. Scanning Electron Microscope (SEM) and EDS analysis results showed that an amount of 1 wt% NiO dissolved in the 8Y-CSZ and insoluble NiO in the 8Y-CSZ precipitated at the grain boundaries. Electrical conductivities of undoped and 1 wt% NiO doped 8Y-CSZ specimens were measured using a frequency response analyzer (impedance spectroscopy) in the frequency range of 100 mHz-13 MHz and at 300-800 °C. Electrical conductivity results showed that grain interior, grain boundary and total conductivity of 8Y-CSZ increased with 1 wt% NiO addition. The reason for increase of electrical conductivity in NiO doped 8Y-CSZ, due to create oxygen vacancies in the crystal lattice of dissolved NiO in 8Y-CSZ and the ion transfer of the oxygen vacancies at high temperatures.