How Do Sacrificial Anodes Work?

Galvanic anodes, or sacrificial anodes, are used in galvanic cathodic protection systems to extend the life of the steel structure they are protecting. This guide explains what they are, how they work and the different types available.

WHAT ARE SACRIFICIAL ANODES?

Galvanic anodes (also commonly known as sacrificial anodes) are highly active metals that are used within cathodic protection systems. They effectively prevent or dramatically slow down the oxidation reaction or degradation of the parent steel material most commonly seen as rust.

Galvanic anodes are created from a metal alloy with a more negative electrochemical potential than the metal it will be used to protect. This is why they are often known as sacrificial anodes, as the anode metal is "sacrificed" and so the anodes corrode or are consumed instead of the parent metal.

HOW DO SACRIFICIAL ANODES WORK?

Galvanic or sacrificial anodes work because they have a stronger or more negative electrochemical potential than the potential of the metal that they are protecting. These sacrificial anodes are then said to behave anodically while the parent metal structure is said to behave as a cathode as the anode is slowly consumed through time while the metal structure remains protected.

With the flow of electrons in one direction, the current will flow between the cathode and anode in the opposite direction.