The morphol. examn. and study of the crystal structure of oxygen-evolving dimensionally stable anodes (DSA) (Ti/IrO2-Ta2O5) has shown that the deposit takes the form of a cobble-stone road because of the thermal shock following its prepn. at 550 Deg. Also appearing in the deposit are agglomerates consisting of epitaxial crystals of IrO2. The catalytic activity and the efficiency are max. for one compn. of deposit which corresponds to 70% IrO2 and 30% Ta2O5. An increase in the catalytic activity and in the efficiency of the electrode can be attributed to the addn. of Ta2O5 to the deposit with the corresponding increase in electrochem. active sites. Anal. of the deposit compn. during accelerated ageing tests has shown that the degrdn. of the optimal compn. proceeds uniformly at each layer. However, the non optimal deposit shows a preferential dissoln. of IrO2. [on SciFinder (R)]