Introduction to Corrosion Kinetics

Thermodynamic principles can help explain a corrosion situation in terms of the stability of chemical species and reactions associated with corrosion processes. However, thermodynamic calculations cannot be use to predict corrosion rates. When two metals are put in contact, they can produce a voltage as in a battery or electrochemical cell.

The material lower in what has been called the 'galvanic series' will tend to become the anode and corrode while the material higher in the series will tend to support a cathodic reaction. Iron or aluminum, for example, will have a tendency to corrode when connected to graphite or platinum. What the series cannot predict is the rate at which these metals corrode. Principles of electrode kinetics have to be used to estimate these rates.