Sacrificial Anodes for Cathodic Protection

Cathodic Protection is a method expended to regulate the erosion of a metal surface by making it the cathode of an electrochemical cell. Sacrificial anodes are exceedingly active metals that are spent to avoid a less active material surface from disintegrating. Sacrificial anodes are made from a metal compound with a more deleterious electrochemical capacity than the other metal it will be used to guard. The sacrificial anode will be expended instead of the metal it is shielding, which is why it is represented as a “sacrificial” anode.


The matters utilized for sacrificial anodes are either moderately uncontaminated active metal, for example a ZINC Sacrificial Anode or magnesium, or are magnesium or aluminum composites that have been precisely formed for use as sacrificial anodes. In treatments where the anodes are concealed, a distinct back-fill substance encases the anode so as to certify that the anode will yield the anticipated production.


As the sacrificial anode functions by presenting another metal exterior with a more deleterious electronegative and considerably more anodic surface, the flux will stream from the recently presented anode and the sheltered metal becomes cathodic, producing a galvanic cell. The corrosion effects are transported from the metal exterior to the galvanic anode and will be forfeited in support of the sheltered metal construction.

For edifices such as elongated conduits, where inert galvanic cathodic defense is not satisfactory, and outer DC electrical power source is utilized to deliver satisfactory current.

Cathodic defense systems guard an extensive array of metal constructions in numerous settings. Customary uses are:

  • Steel water or fuel conduits
  • Storage tanks, for example domestic water heaters
  • Steel dock piers
  • Ship and boat structures
  • Offshore oil boards
  • Onshore oil well coverings
  • Metal support bars in concrete structures and edifices
  • Galvanized steel, in which a sacrificial covering of zinc on steel parts shields them from corrosion

In certain situations, cathodic defense can avert stress erosion splitting.

Though there are several linear differences on how a cathodic defense system can be connected, there are merely two straightforward approaches to utilizing cathodic defense.

1. Sacrificial anode cathodic fortification (connecting galvanic anodes)
2. Impressed current cathodic defense (connecting repaired anodes)



Sacrificial Anode Types

Sacrificial Anode Types



Useful Advantages of Utilizing Cathodic Defense

  • Decrease in the price of set-up erosion
  • Decrease in structure catastrophes
  • Decrease in product loss due to corrosion
  • Reduction in interruption for emergency upkeep
  • Escalated structure service existence
  • Augmented level of substructure service to clients
  • Improved well-being and refuge to submerged substructure

Once assembly of a new submerged or immersed system is being intended, corrosiveness of the atmosphere must be deliberated as one of the issues in the planning of the structure. If understanding with comparable systems in the locality of the construction location has revealed that the site situations are destructive centered on leakage and malfunction accounts, cathodic defense must be deemed as a way to limit rust on the new structure.

Cathodic defense is one of the limited approaches of erosion regulation that can be successfully used to regulate deterioration of current suppressed immersed metal exteriors.

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