Effect of DC voltage on the microstructure and electrical properties of stabilized-zirconia1
Y2O3 and Al2O3 codoped ZrO2 specimens were treated by a DC voltage of 8 V at 600°C in air. During the treatment, electrons were injected from the cathode into the ZrO2, thus colour centers were formed. After the treatment, no structure and valence state changes were detected by XRD and XPS, and no obvious microstructure and composition change were observed by TEM and EPMA. However, the bulk resistance was found to greatly increase, which is considered to be the result of the formation of colour centers. The grain-boundary resistance was found to greatly decrease, and this phenomenon may be due to a reduced space-charge potential and the reduced size and amount of the amorphous grain-boundary phase.