What is cathodic protection?

Cathodic protection helps prevent corrosion on a metal surface. In this month's Galvanizing Today article, we explain in detail what cathodic protection is, its different types, and the benefits of cathodic protection for steel, especially in the context of hot dip galvanizing.

Cathodic protection explained

Each type of metal has an different electric potential, or the amount of potential electricity it can hold. When two different types of metal come together, provided they have dissimilar potential, the metal with more electro-negative potential will “sacrifice” itself and corrode before the metal with less electro-negative potential.

There are two types of cathodic protection. One is achieved by supplying a direct current (DC) from an external source, known as impressed current cathodic protection. The other makes use of sacrificial anodes, known as galvanic anode or sacrificial anode cathodic protection.

Benefits of cathodic protection

By preventing corrosion, cathodic protection extends the lifespan of metal structures, reducing the amount of replacements or repairs needed. This helps to save time and money on refabrication.

The extended lifespan given to the steel also means that it becomes a more sustainable solution than steel without cathodic protection, by reducing emissions associated with transport and refabrication.

Cathodic protection also helps to make vital steel fabrications such as structural steel more safe to use. Corrosion poses a significant threat to steel which can, in turn, create serious safety hazards. The extended lifespan given by cathodic protection helps to ensure that the steel remains reliably safer to use for longer and saves on downtime associated with maintenance.

Galvanizing provides cathodic protection

The hot dip galvanizing process provides galvanic anode cathodic protection for steel. The metal fabrication is dipped into a bath of molten zinc, causing a reaction that makes the zinc bond to the underlying steel. This occurs because zinc has more electro-negative potential than iron, causing the zinc to corrode first.

The cathodic protection provided through hot dip galvanizing means that it is a much more effective and long-lasting coating method than alternatives such as paint.

A high quality coating

Although hot dip galvanizing is very effective at corrosion protection, it’s important to ensure the process is carried out correctly by a trusted galvanizer.

A high-quality galvanizing company will ensure the galvanized finish looks smooth, shiny, and aesthetically appealing.

Have you learnt something new about the types of steel protection? Let us know in the comments.