Study of the alternating current electrical properties of ZrO2–7.5 mol% Y2O3 ceramics at room temperature and at 457–595 K

• DOI: 10.1007/s100080000177
• Publication Date: 2003-03-05T12:23:11Z
• Authors: Aigars Vītiņš
• Keywords: Atmospheric temperature range

The impedance of a ZrO2–7.5 mol% Y2O3 ceramic specimen was measured using the two-probe technique in the frequency range 20 Hz–1 MHz at room temperature and in the temperature range 457–595 K. The novelty of the research lies in the analysis of the intragrain part of the impedance spectra of the ceramics on the basis of the approach proposed in the literature for impedance of ZrO2–Y2O3 single crystals. The method to determine a value of the intragrain direct current electrical conductivity from an impedance spectrum has been developed. The frequency dependence of the intragrain complex dielectric response was interpreted according to the common model used in the literature. Frequency domains, where a power-law dependence having different exponents n1=0.825–0.844 and n2=0.571–0.592 is observed, were found. The inner consistency of the model used is verified. Values of the transition frequency and the relaxation frequency were determined for the grain interiors and compared with each other. The values of the activation energies of the direct current conductivity, the transition frequency and the relaxation frequency are found to be the same within experimental uncertainty in the temperature range 457–523 K.