Galvanic Anode

Definition - What does Galvanic Anode mean?

A Galvanic Anode, also known as a sacrificial anode is a component of the cathodic protection system that prevents corrosion to equipment working under corrosive environments. Galvanic anodes are made up of metals or metal alloys which are more actively charged than the metal equipment that needs to be protected. This metal equipment that needs to be protected is turned into a galvanic cathode. The potential difference between the cathode and anode, i.e., between the two metals leads to corrosion of the metal that is more actively charged and thus, galvanic anode sacrifices itself to protect the equipment kept on galvanic cathode side.

Petropedia explains Galvanic Anode

Galvanic cathodic protection (CP) controls the corrosion of a metal by using a galvanic anode as a sacrificial metal in an electrochemical cell. This is achieved by placing the metal to be protected in contact with another, more easily corroded metal to act as the anode of the electrochemical cell.

A galvanic cathodic protection system is commonly used in:

  • Steel pipelines and storage tanks
  • Ship hulls
  • Offshore oil platforms and onshore oil well casings
  • Metal reinforcement bars in concrete
  • Galvanized steel

Galvanic or sacrificial anodes are made in various shapes using alloys of zinc, magnesium and aluminium. The following are some of the advantages of using sacrificial anodes:

  • Can be used where there is no power
  • Lower initial cost
  • Less supervision required
  • Comparatively simple installation and additional anodes can easily be added if the initial installation proves to be inadequate.
Metal alloys that are kept at the anode side in the galvanic anode cathodic protection system must be periodically inspected and replaced.
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