Measurement of the t→m and m→t transformations in Ce–TZP by dilatometry and impedance spectroscopy

The thermally induced t→m and m→t phase transformation of 9 mol% CeO2-stabilized ZrO2 with mean grain sizes varying from 1.2 to 2.7 μm has been characterized by dilatometry, XRD and impedance spectroscopy. XRD analysis indicates an increase in the volume fraction of the monoclinic phase from 0.69 to 0.89 with increasing grain size, which could be quantitatively correlated with the impedance spectra of the materials. Based on these findings, the m→t retransformation could be studied in situ by impedance spectroscopy in the temperature range from 20–350 °C. Depending on the grain size, the changes in the capacitive and resistive parts of the electrical impedance correlate well with the retransformation ranges obtained by dilatometry. Therefore, impedance spectroscopy is a useful analytical tool to study the transformation behaviour of zirconia ceramics.