The phenomenon of electromechanical failure of zirconia has been examined. It is shown that spatial variation of electronic conductivity in a predominantly oxygen ion conductor can lead to internal precipitation of molecular oxygen and its pressurization. Internal pressures high enough to crack zirconia can develop if the electronic conductivity is higher on the oxygen exit side. The calculations demonstrate that the kinetics of pressurization are very sensitive to the relative magnitudes of the electronic and the ionic conductivities. Oxygen was electrolyzed at 800°C through zirconia solid electrolytes with lanthanum strontium manganate (LSM) electrodes under an applied dc potential of 1.0 V. Spalling of the solid electrolytes was observed. Composite disk electrolytes were fabricated such that part of the disk contained Ti02 as a dopant which was added to enhance the electronic conductivity. The electrolytes exhibited severe cracking and pitting when the TiOz-doped region was on the oxygen exit side. No degradation occurred when the TiOzdoped region was on the oxygen entry side. Implications regarding the use of mixed conductors as dense electrodes in electrochemical systems are discussed. [

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The d‐c polarization technique, relaxation technique, and the charge transfer technique have been applied to cuprous chloride single crystals for the determinations of electronic conductivity, mobility of electronic carriers, and the double layer capacitance at normalCuCl/normalgraphite interface. A method to separate the electronic charge transfer is presented. It has been shown that the redistribution of electronic carriers within the solid electrolyte in which the concentrations of electronic carriers exponentially increase with the applied potential may make a significant contribution to transient measurements involving a polarization cell. Further, ideal polarization kinetics were observed for the normalCuCl/normalgraphite interface in the temperature range of 200°–300°C, because the electronic charge transfer was made negligible by selecting the proper parameters such as thickness of the electrolyte and the magnitude of the applied potential step normalΔEfalse(E1‐E2false) as well as the values of the applied potentials, E1 and E2 , on the polarization cell.

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