The risk of corrosion can be costly to your business, which is why organizations in the oil & gas industry protect their biggest and most important metal assets with cathodic protection. This article details all the basics of corrosion and cathodic protection services for your business.
What is corrosion?
Corrosion is a naturally occurring process that deteriorates unprotected metal structures. For this electrochemical phenomena to occur, two dissimilar metals must be submerged in an electrolytic substance, such as concrete, soil, or water.
When the right elements are in place, free electrons form a metal conducting pathway between the two metals. These free electrons move from the anode (active metal) to the cathode (less active metal). If the free electrons do not reach the destination before the arrival of oxygen, ions on the active site recombines to produce rust and deteriorate the active metal.
How does cathodic protection work?
Cathodic protection services, also known as CP, are used all over the globe to protect metals in environments susceptible to corrosion. In the oil and gas industry, CP is an extremely important technique used to mitigate damages on buried or immersed structures, such as pipelines.
To stop the occurrence of corrosion, CP connects the base metal at-risk (steel) to a “sacrificial” base metal designed to corrode in lieu of the base metal. This technique offers protection to the steel by providing a highly active metal that acts as an anode and offers free electrons. When free electrons are introduced, the active metal responds by sacrificing its own ions, which prevents the less active steel from corroding.
Types of Cathodic Protection
There are two ways to apply CP to your base metal: galvanic and the impressed CP system.
Galvanic
Galvanic CP refers to the application of a protective zinc coating to the at-risk steel. The zinc corrodes in place of the encapsulated steel to prevent rusting. Although more affordable than the latter, galvanic systems have a limited life span. Over time, the sacrificial anode will degrade until it is no longer capable of supplying protection.
Impressed Current CP
Impressed current CP systems differ from the galvanic system. Rather than coat the at-risk steel, anodes are connected to a power source to provide a lasting electrical flow. The anode (usually alloys such as aluminium, magnesium, or zinc) is more active than the base metal and has a greater electrochemical potential. Because the anode has an unlimited power source, it provides a more extended protection than a sacrificial anode can on its own.
Have more questions about cathodic protection services for your business or organization? We can help. Learn more about cathodic protection by reaching out to the experts at Hawkins. From consult to design and install Hawkins has the experienced personnel to assist you with all phases of your cathodic protection needs.