Galvanic corrosion is an electrochemical phenomenon in which a metal corrodes more readily when it is in electrical contact with a dissimilar metal and both are in contact with an electrolyte (like water or saltwater).
The two metals, due to their different electrode potentials, form a simple electrochemical cell. The more active (less noble) metal acts as the anode and accelerates its own degradation, dissolving rapidly into the electrolyte.
Conversely, the less active (more noble) metal acts as the cathode, where corrosion is inhibited. This cell requires three components: dissimilar metals, an electrical contact, and an electrolyte. Understanding this mechanism is vital for resilient engineering and material selection.