NONSTATIONARY ELECTROCHEMICAL RESPONSE OF POLYCRYSTALLINE CADMIUM IN SODIUM-HYDROXIDE SOLUTIONS

The anodization of cadmium in NaOH solutions produces a hydrous cadmium hydroxide-cadmium oxide layer and soluble cadmium species in solution. These processes are investigated through conventional voltammetry, potentiostatic, rotating ring disc electrode and complex voltammetric techniques by using NaOH solutions in the 0. 01-1 M range at 25 degree C. The threshold potential of the anodic reaction is very close to the reversible potential of the Cd/Cd(OH)//2 electrode. The overall anodic and cathodic reactions can be interpreted through a complex reaction model comprising a number of parallel reactions following the initial formation of CdOH//a//d species at the electrode surface level.