Anodic Polarization Characteristics Of Gold and Silver In Chloride and Sulfate Media

Abstract

Abstract The anodic polarization characteristics of gold and silver in chloride and sulfate media have been studied, employing potentiostatic techniques. It was found that gold produces an active-passive S-shaped curve, the form of which is not seriously affected by the presence of oxygen in the electrolyte. The stability of the passive state was greater in the sulfate than in the chloride media. Silver does not give a typical anodic polarization curve in NaCl solution, because formation of an AgCl film is the primary anode reaction. This film thickens and exfoliates at a current density of 2 a/sq ft. For this reason, silver could not be used as an inexpendable anode in an impressed current system containing chloride ions.