Low pressure oxygen direct current discharges with ion conducting yttria stabilized zirconia electrodes

Oxygen direct current (DC) discharges with metal electrodes are in most aspects well understood with respect to the discharge characteristics and the composition of the different ionic species and electron properties. Here we report on DC discharges where the metal electrodes of a DC discharge are replaced by an oxygen ion conducting ceramic. For this purpose we used polycrystalline yttria stabilized zirconia (YSZ) electrodes and (100) oriented YSZ single crystals doped with 9.5 mol% Y2O3. We investigated three different discharge cells: symmetric cells with two YSZ electrodes, asymmetric cells with one YSZ and one platinum electrode and for reference purpose a symmetric cell with two platinum electrodes. The discharges were characterized by current-voltage measurements and optical emission spectroscopy. Results are reported for electrode temperatures between room temperature (25 °C) and 853 °C and oxygen pressures of about 50 Pa. We demonstrate that it is possible to affect directly the concentration of ionic species in an oxygen DC discharge by using ion-conducting electrodes.