Voltammetry on BIMEVOX.10 (ME=Cu, Ni, Zn, Mg) microsamples

High temperature cyclic voltammetry on microsamples was used for the investigation of the electrochemical stability of BIMEVOX.10 materials. The electrochemical measurements were performed on a three-electrode cell of the type: Pt|microsample|YSZ|Pt with the interface Pt|YSZ as a pseudo reference electrode. The experiments were performed in nitrogen containing a small quantity of oxygen. The cell consisted of a disc of yttria stabilized zirconia (YSZ) with platinum paste electrodes for the counter and the reference electrode. The working electrode was a small platinum plate which contacts the microsample and presses it onto the surface of the YSZ disc. In general, the stability of BIMEVOX.10 is determined by the stability of the main compound Bi2O3. None of the samples exhibited a substantially higher stability against complete reduction than BICUVOX.10. Nevertheless slight differences in the reduction processes at less negative potentials than the standard potential of Bi2O3 have been observed. Redox processes in this potential region could be related to valence changes of vanadium from V5+ to V4+ and, at more negative potentials, from V4+ to V3+.