Sacrificial anode

An electrochemical technique for controlling corrosion by making the metal structure the cathode of an electrochemical cell, using either sacrificial anodes or an impressed current system. It is widely combined with protective coatings on pipelines, ships, jetties and offshore structures.

Accelerated corrosion of the less noble material when two dissimilar conductors are electrically connected in an electrolyte such as seawater. Carbon fibre composites in contact with aluminium or steel can drive galvanic attack, so joints are isolated with sealants, coatings or an insulating glass ply.

The process of coating steel or iron with zinc by immersion in a bath of molten zinc, forming metallurgically bonded zinc-iron alloy layers with an outer zinc surface. The coating protects both as a barrier and sacrificially, continuing to protect the steel at small areas of damage.