Corrosion refers to a process that involves deterioration or degradation of metal. The most common example of corrosion is the degradation of metals or alloys. Most corrosion phenomena are electrochemical in nature and consist of at least two reactions on the surface of the corroding metal. One of the reactions is the oxidation (e.g., dissolution of iron), also referred to as the anodic partial reaction. The other is a reduction reaction (e.g., reduction of oxygen), and is referred to as the cathodic partial reaction. The products of the electrochemical reactions can react chemically with each other to form the final product (e.g., rust).