Investigation of the complex conductivity of nanocrystalline Y2O3‐stabilized zirconia

Abstract

AbstractNanocrystalline ZrO2‐ and Y2O3‐powders with grain sizes from 5‐20 nm were prepared by the Inert Gas Condensation method. The powders were mixed in different fractions, pressed into green bodies and sintered to ceramic samples with 35‐49 nm average grain size. The phase, grain size and specific surface area of the powders and ceramic samples was characterized by X‐ray diffraction and nitrogen adsorption. Densities from 82 to 93% of the single crystal density were determined using the Archimedes principle. The complex conductivity was measured for frequencies ranging from 20 Hz to 3 MHz at temperatures between 80 and 1100 K. The lattice relaxation, grain boundary relaxation and the contact process could be resolved and identified. The dc‐conductivity for the lattice and the grain boundaries were deduced from the data. The activation energies for dc‐conductivity were determined for the lattice and the grain boundaries as 0.85 ± 0.05 and 1.0 ± 0.1 eV, respectively.