The effect of anionic composition of electrolytes on the anodic dissolution of iron-family metals

The anodic dissolution rate of the iron-family metals is analyzed depending on the anionic composition of aqueous electrolyte solutions. Investigation of the process in a broad range of potential values (including the limiting current range) in solutions with the controlled content of cations and anions enables us to discover the diffusion limitations at a stage of anion supply to the electrode-electrolyte interface and show the importance of processes in the electrolyte layer near the electrode. During the anodic process, anions, which are present in the solution, act not only as counterions balancing for change balancing of the positive metal ions formed at the interface, but also as depolarizers of the anodic process. Upon the formation (or at the moment of appearance), metal ions interact with the anions to form ion pairs that may exist and move independently. The supply of “free” anions to the electrode surface controls the process rate in the limiting current range.