Galvanic Corrosion. Galvanic corrosion (also called ' dissimilar metal corrosion' or wrongly 'electrolysis') refers to corrosion damage induced when two dissimilar materials are coupled in a corrosive electrolyte. It occurs when two (or more) dissimilar metals are brought into electrical contact under water.
Just so, how is galvanic corrosion caused?
What causes galvanic corrosion? Different metals and alloys have different electrochemical potentials (or corrosion potentials) in the same electrolyte. The potential difference (i.e., the voltage) between two dissimilar metals is the driving force for the destructive attack on the active metal (anode).
Where does corrosion occur in a galvanic cell?
The anode is the electrode where oxidation (loss of electrons) takes place; in a galvanic cell, it is the negative electrode, as when oxidation occurs, electrons are left behind on the electrode. These electrons then migrate to the cathode (positive electrode).
How does corrosion occur?
In the presence of moisture, an oxidation reaction takes place on the energized area of the metal surface to elute metal as an ion (anode). On the metal surface, oxidation on anode and reduction on cathode proceed in equal rates and metal corrosion takes place. Normally, corrosion of metal occurs on anode.