What are sacrificial anodes used for?

Sacrificial anodes are used to protect metallic structures, such as pipelines, tanks, or ship hulls, that are exposed to corrosive environments.

Their function is based on the principle of cathodic protection: the sacrificial anode, made of a less noble metal than the structure being protected (for example, zinc or magnesium), corrodes in place of the structure.

Here’s how the process works:

Electrochemical reaction:

When a metal structure is immersed in a corrosive environment (such as soil or water), electrochemical cells form, causing corrosion of the metal. By adding a sacrificial anode, a circuit is created in which the anode has a lower electrical potential than the main metal structure, causing it to corrode first.

Protection of the structure :

Since the anode is the part that corrodes, the metal of the structure remains intact or experiences very minimal deterioration. Essentially, the anode sacrifices itself to protect the structure.

Periodic replacement:

Over time, the anode wears out and loses effectiveness, so it needs to be replaced periodically to keep the cathodic protection active.

In summary, sacrificial anodes divert corrosion toward themselves rather than toward the structure being protected, extending its life and reducing the need for maintenance.