Electrical properties of ZrO₂ in nano- and polycrystalline states at high pressure

We present the results of the research work devoted to the problem: how the crystallites influence the electrical properties of stabilized zirconia at pressures of 22−50 GPa and in the temperature range of 77−450 K. The measurements were conducted in the highpressure chamber under direct current on nanocrystalline powders of ZrO₂ stabilized by Pr (0.5%) and on compact powder samples of «partially stabilized» ZrO₂ including 5% Y₃P₃. The nanocrystallite size equals 10, 12 and 56 nm. The change of electronic properties of stabilized zirconia at 31.5–37.5 GPa, 40–44 GPa and 45.5–48.5 GPa in nano- and polycrystalline states has been discovered. It gives us a possibility to verify the phase diagram of ZrO₂ at those intervals of pressure. Besides, it has been revealed that stabilization as nanocrystallinity leads to appearance of additional mechanisms of conductivity in ZrO₂