A sacrificial anode is a key component of a corrosion prevention technique known as cathodic protection.

It is a block of a highly reactive metal, like zinc, aluminum, or magnesium that is intentionally attached to the metal structure you want to protect. The principle is based on galvanic corrosion: the sacrificial anode corrodes preferentially, essentially "sacrificing" itself by donating electrons. This protects the main structure from rusting or other forms of deterioration. It is an essential and widely used method for extending the lifespan of vital infrastructure like pipelines, ship hulls, and offshore platforms.