Abstract

Among the numerous base metals tested for DSA type electrodes (e.g., titanium and its alloys, zirconium, niobium etc.), tantalum is a potentially excellent substrate owing to its good elec. cond. and corrosion resistance, and the favorable dielec. properties of its oxide. Nevertheless, a DSA type electrode fabricated on a tantalum substrate would be very expensive due to the high cost of the metal. To prep. an anode combining the excellent properties of tantalum at reasonable price, a new material was developed in the authors' lab. This consists of a common base metal (e.g., Cu) covered with a thin tantalum coating. This tantalum layer was obtained by molten salt electroplating in a LiF-NaF-K2TaF7 melt at 800 Deg. Thus, an anode metal/Ta/Ta2O5-IrO2 with a surface load of 22 g m-2 IrO2, submitted to the severe test conditions used exhibits a standardized lifetime 10-fold greater than one made with ASTM grade 4 titanium base metal. Thus, this type of electrode might be advantageously employed as an oxygen evolution anode in acidic solns. [on SciFinder (R)]

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