What is corrosion
It is a natural and spontaneous electrochemical process in which a metal undergoes a loss of material, transforms into oxides, and loses its properties. Material loss (corrosion) occurs at the anode, and it suffers a loss of electrons with subsequent transfer through the metal / electrolyte interface.
For the corrosion reaction to take place, the presence of all of the following elements in the corrosion cell is required, assuming the anode and the cathode are connected:
Therefore, the basic corrosion reaction is:
- Anodic reaction: Me → Me n + + ne-
- Cathodic reaction: 2H + + 2e- → H2
The anodic reaction (oxidation) releases electrons through the passage of the metal to the electrolyte in the form of positive ions (cations).
The cathodic reaction (reduction) occurs on the metal surface in which the electrons produced at the anode combine with certain ions present in the electrolyte.