What Is Cathodic Protection?

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Corrosion is a natural process that can deteriorate metal structures and cause costly damage for your business.

Cathodic protection can be used to mitigate corrosion damage to active metal surfaces. Cathodic protection is used all over the world, protecting pipelines, water treatment plants, above and underwater storage tanks, ship and boat hulls, offshore production platforms, reinforcement bars in concrete structures and piers, and much more.

Cathodic protection is typically used to protect steel from corrosion. Corrosion is caused when two dissimilar metals are submerged in an electrolytic substance such as water, soil, or concrete. Free electrons move from one metal to the other, from the more active metal (anode) to the less active metal (cathode).

However, some of the free electrons may combine with oxygen to produce ferrous oxide, better known as rust, if they do not reach the cathode.

Cathodic protection connects the base metal at risk (generally steel) to another metal that is then ‘sacrificed’ and allowed to corrode. This technique preserves the steel by providing a highly active metal to act as the anode and provide free electrons.

Introducing the free electrons means the anode sacrifices its ions, preventing the cathode from corroding.

There are two basic types of cathodic protection: galvanic, and impressed current cathodic protection.

Galvanic protection consists of the placation of a protective zinc coating to steel to prevent rusting. The zinc is then allowed to rust instead of the steel. However, this system has a limited life span, as the zinc coating will corrode until it is no longer providing any protection.

Impressed Current Cathodic Protection systems consist of anodes that are connected to a power source, providing a perpetual source of electrical flow. The sacrificial anode materials, usually metals such as aluminium, magnesium, or zinc, have a stronger electrochemical potential, and the power source means that protection is provided for much longer.

To sum up, cathodic protection is a commonly used method to protect steel structures but does require routine maintenance and replacement. If you need cathodic protection systems, talk to us today.

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