Further studies on periodic phenomena in passivating systems

Abstract

The SR and PNJ mechanisms of Indira and Doss for explaining potential oscillations in galvanostatic systems have been described. Additional evidence, based on decay studies, in favour of the mechanism has been presented. The SR is shown to give a good picture of passivity and is also useful for explaining the abnormal behaviour of passivated nickel electrodes, and how an apparent coverage of even a fraction of the metal surface by oxygen atoms can cause passivity. A working picture has been given to the potentiostatic curve for nickel in sulphuric acid, on the basis of the SR. The mechanism of various forms of anodic dissolution and related phenomena is discussed in relation to SR and PNJ.