Physico-chemical characterization of highly pure nanocrystalline doped TZP

Yttria and scandia doped nanocrystalline tetragonal zirconia ceramics have been prepared from sintering of spray-pyrolysis powders. The average primary crystallite size after sintering has been found equal to 70 nm from X-ray diffraction line broadening while aggregated particle size of 300 nm has been characterized by scanning electron microscopy (SEM). No trace of segregated Si has been detected in the grain boundaries using wavelength dispersion scanning (WDS). Impedance diagrams show two well-resolved components in the 300–700°C range. Small size of crystallites and existence of nanoporosity give rise to a large grain boundary contribution compared to microcrystallized zirconia.