ABSTRACT
The theoretical picture, or model, indicates that some of the current demand needed to cathodically reduce the dissolved oxygen on the metal surface is now satisfied by the external electrons. Hence, fewer electrons need to be provided by the anodic dissolution of iron atoms. Now, the rate of electron delivery is such that all of the cathodic reduction of dissolved oxygen is sustained by the externally supplied electrons. Benjamin Franklin had coined the expressions “positive” and “negative” to describe the charges involved. Subsequently, as the concept of electric current developed, it was taken as a matter of convention that current flowed from positive to negative poles. Practical electrochemistry is mainly interested in how changes in the potential difference between the metal (steel in this instance) and the electrolyte (seawater) bring about changes to the rates of the anodic and cathodic processes taking place on the surface of that metal.
