MORPHOLOGICAL DETERIORATION OF IRIDIUM OXIDE-TANTALUM OXIDE ANODE BY OXYGEN EVOLUTION

The morphology of an iridium oxide-based anode prepared by thermal dec omposition and its variation during electrolysis at a high current den sity are investigated by SEM observation and elementary analysis using EDX, XRF, and XPS. The surface structure of the IrO2-Ta2O5 anodes is heterogeneous, consisting of cracks, IrO2 crystallites, and smooth are as with microcracks. Some parts of the coating layer gradually drop of f with the increase in the number of cracks during the electrolysis, w hich results in the appearance of the new IrO2 crystallites from the i nside phase of the coating layer. The relation between the morphologic al deterioration and the lifetime of the anode is also discussed.