The potentiodynamic behaviour of iron in alkaline solutions under carefully controlled perturbation conditions reveals that the overall electrochemical process is more involved than was thought earlier. The electrochemical characteristics of the systems are explained through a series of successive conjugated redox coupks principally involving Fe(&), Fe(OH), gnd FeOOH as limiting stoichiometric species. The yield of soluble species such as either FeO:-or HFeO; increases with the pH. Ageing effects of reactants and products are also distinguished through the potentiodyoamic E/I records.

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The potentiodynamic response of the Ni/alkaline aqueous solution interface in the region of the hydrated normalNifalse(OH)2 to β‐normalNiOOH electrochemical reaction reveals that both species undergo phase transformations. The anodic product from the normalNifalse(OH)2 species involves the formation of three species energetically different which are detected during the electroreduction process. Under well‐defined perturbation conditions, a reasonable set of kinetic parameters pertaining to the anodic process is obtained which is formally interpreted through a consecutive three‐step mechanism of reaction involving a charge transfer, a chemical reaction, and a charge transfer and a proton transfer process. Side reactions involving water take into account the various aging processes of the reaction products.

The electrochemical behaviour of nickel in alkaline aqueous solutions within the anodic potential range yielding Ni(OHh and under different potentiodynamic perturbations profiles has been investigated. The formation of Ni(OHh is characterized by an irreversible anodic current peak which is quantitatively interpreted in terms of a complex reaction pathway involving different hydroxoadsorbed slx.~cies.

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