Example

A good example of the electrochemical corrosion process can be illustrated with the corrosion of zinc in a hydrochloric acid environment. Zinc is removed from the surface of the metal and enters the electrolytic solution in ionic form, as shown in Equation 15 and illustrated in Figure 45.

Simultaneously, the two electrons released from zinc are transferred to the hydrogen ion, which is supplied from the dissociation of the acid as shown in Equation 16. Equation 14 shows the association of hydrogen ions to form hydrogen gas upon the transfer of electrons from the zinc.

The overall reaction of zinc with a hydrochloric acid solution can be described as in Equation 17.

The corrosion process for other metals in like solutions is similar to that illustrated in this example; however there are other corrosion mechanisms for metals in different types of environments.