ON THE EFFECTS OF THE ELECTRONIC SUBSYSTEM OF AN ELECTROLYTE ON THE ELECTROCAPILLARY BEHAVIOR OF A LIQUID-METAL OXIDE SOLID-ELECTROLYTE INTERFACE

The interface between a liquid metal and HfO2-15 mol % Me2O3 solid ele ctrolyte (where Me = Y, Gd, or Dy) was studied. Measurements were take n for Sn and Pb in a H-2-H2O (13.3 Pa) atmosphere and T = 973 K under cathodic polarization. The potential dependence of conductivity for th e metal/electrolyte interface G showed two minima. These minima corres pond to two maxima of free surface energy: E(max)I and E(max)II. The E (max)I and E(max)II values depend weakly on the nature of the stabiliz ing agent; they are substantially determined by the nature of the base oxide (HfO2 or ZrO2). These values shift to negative E values when go ing from a HfO2-based oxide to a ZrO2-based oxide. The difference E(ma x)II - E(max)I measured in the HfO2-15 mol % Me2O3 electrolyte is in s ubstantial agreement with that measured earlier for ZrO2-10 mol % Y2O3 in an atmosphere of H-2-H2O and CO-CO2. The E(max)I and E(max)II maxi ma are adsorptive in nature. Moreover, the E(max)II maximum can be str ongly affected by defects of the F+-center-type; these defects emerge as a result of the partial reduction of electrolyte owing to an increa se in the electronic component of its conductance sigma(e). It is beli eved that the relative values of the E(max)I and E(max)II potentials a re determined by the p-n transition point in oxide electrolyte.