Steady-state anodic dissolution of iron in neutral and close-to-neutral media

In neutral and close-to-neutral solutions, which contain no surface-active substances, iron dissolves via a two-step scheme. The transfer of the first electron across the interface involves water molecules that dissociate during the adsorption; the transfer of the second electron limits the process under steady-state conditions. In parallel, a passivator, namely, adsorbed oxygen is formed via a similar scheme. The passivator is removed from the surface due to its chemical reaction with hydroxonium ions, water molecules, or hydroxide ions. The process is adequately described by a mathematical model based on an assumption that the metal dissolves from an energy-uniform surface free from passivating species.