Galvanic corrosion occurs due to:

Galvanic corrosion occurs when two dissimilar metals are in electrical contact within an electrolyte, leading to the establishment of a galvanic cell. In this process, one metal (the anode) corrodes at an accelerated rate due to the electrical current that flows from the more electronegative metal (the cathode) to the anode. The difference in electrochemical potential between the two metals creates conditions that facilitate this type of corrosion.

In practical terms, when these metals are exposed to an electrolyte, such as seawater or moisture, the rate of corrosion significantly increases for the metal that serves as the anode. Hence, the presence of an electrolyte is crucial, as it completes the circuit and allows current to flow. Understanding this fundamental principle of galvanic corrosion assists in mitigating its effects in various applications, especially in marine environments, where dissimilar metals are often used in close proximity.

The other factors mentioned—such as exposure to saltwater, temperature variations, and mechanical stress—can influence corrosion processes but are not specifically the cause of galvanic corrosion. While saltwater can act as an electrolyte and heighten the risk of galvanic corrosion, it is the relationship and electrical interaction between dissimilar metals that fundamentally define this corrosion type.