L'effet d'anode lors de l'électrolyse des sels fondus—I. Étude intentioncinétique et mesure des temps d'induction

Abstract

A galvanostatic study of the anode effect during the electrolysis of NaF-ZrF 4-ZrO 2 mixtures has shown the influence of composition (ZrF 4 and ZrO 2 content), temperature, pressure, and the diameter and form of the anode, on the critical cd at which the effect appears. No appreciable rise of temperature at the bottom of the anode was observed. Further, although the surface of an anode that has undergone the anode effect shows on X-ray analysis an additional, unidentified line, no insulating layer on the anode surface was observed. Measurement of the induction period for the anode effect confirmed some of the galvanostatic results. Although it seems square-wave current could not be realized, true that the onset of the anode effect is linked with diffusion phenomena. Oscillograms recorded at high sweep rates show that as soon as the anode effect becomes manifest at low potential, it seems to appear and disappear at a high frequency, which leads to a mixed functioning of the anode, with and without the anode effect.