ELECTROLYTIC FORMATION OF SILVER IN THE AGNO3-AGCL MELT

The influence of the cathode material (tungsten, platinum, iridium, gl assy carbon) and its pretreatment on the formation of silver in the Ag NO3 + AgCl (25 mol %) melt is studied galvanostatically at 180-300 deg rees C. Adding AgCl makes the cathode surface more active, probably be cause of a better solubility of the oxide film on the substrate, which is manifested in a decreased nucleation overvoltage. The most indiffe rent cathode material in the melt is glassy carbon. The substrates can be rendered more indifferent by increasing potential of anodic treatm ent of the cathode and by temporarily overheating the melt, as in pure AgNO3. The double-layer capacitances, nucleation constants, equilibri um concentrations of adatoms on the iridium substrate, and the number of atoms in the critical nucleus are determined.