Which Sacrificial Anodes is Best for the Cathodic Protection System?

Apr 02, 2021

Which Sacrificial Anodes is Best for the Cathodic Protection System?

The sacrificial anode needs no more external power source comparing with the MMO anode in the ICCP system, it is economical and easy to install. The low voltage and current between the sacrificial anode and the surface will not generate stray current, it protects the system infrequently and makes overprotection is unlikely to happen.

Magnesium anode, aluminum anode, and zinc anode are the most used sacrificial anode in the cathodic protection of the galvanic system. But which one is the best?

Generally, Magnesium anode is the most widely used metal in sacrificial anodes for underground structures and certain aqueous environments. Mg anode has the highest driving potential of sacrificial anodes. It is used for most direct U/G applications and in higher resistivity, aqueous electrolytes. They are available in a wide variety of forms and weights for many kinds of applications.

Aluminum anode makes an attractive sacrificial anode material, especially in low resistivity applications such as seawater and produced brines. Al anode has a lower driving potential than Mg anode and higher current capacity than Zn anode, and these are important traits for its use in the long-life saline system.

Zinc anodes are usually applied in low resistivity soils below 1,000 ohm-cm and in seawater or produced brines. Zinc is excellent when used as electrical grounds and special 99.99% pure Zinc is used as permanent reference electrodes under tank bottoms and inside vessels.