Corrosion is a natural degradation process of a material caused by chemical or electrochemical reactions when the material is in contact with its environment. The general mechanism of iron (metal) corrosion is understood by an electrochemical process, where oxidation of iron leads to the formation of iron oxides, commonly known as rust. The corrosion mechanism begins with the iron surface losing electrons at anodic sites, making ferrous (Fe 2+ ) ions (eq.1). At the cathodic site, these electrons are consumed by water and oxygen to form hydroxyl ions (eq.2). Instead of reducing oxygen, hydrogen ions (H + ) can also be reduced to produce hydrogen gas (H2) in an acidic environment (eq.3). Then, the ferrous ion can react with hydroxyl ions to form ferrous and ferric hydroxides (Fe(OH)2 and Fe(OH)3, respectively) as shown in eqs 4 and 5.