What is corrosion?

Corrosion is the gradual destruction and degradation of materials through chemical and/or electrochemical reaction with their environment. There are several different types of corrosion that can occur and, in this post, we take a look at one specific type of corrosion – pitting corrosion – through two case studies from different industries.

Why is corrosion a problem?

Corrosion is a dangerous and extremely costly problem across a wide range of industries. In the most serious of cases, it can cause buildings and bridges to collapse, oil pipelines to break and chemical plants to leak.

Below we take a look at a case study which demonstrates how not implementing a corrosion prevention solution resulted in severe pitting corrosion.


Severe pitting corrosion at a petrochemical plant

At a petrochemical plant in Southeast Texas, USA, multiple areas of carbon steel pipework were suffering from heavy corrosion which had resulted in major pitting.

Close-up of heavy corrosion and pitting to one of the pipes
Close-up of heavy corrosion and pitting to one of the pipes

The severity of this pitting had caused the pipe walls to thin in many areas and completely through the wall in one spot, which resulted in a leak.

Original leak and new through-wall due to blast
Original leak and new through-wall due to blast

Firstly, a solution was needed to fix the live leak. A fast curing epoxy-based metal repair composite (Belzona 1211) was used to fix the live leak. This solution can be used for both permanent and emergency repairs, and cures at room temperature with no hot work involved.

Epoxy-based composite applied to fill the pits
Epoxy-based composite applied to fill the pits

Once the live leak had been sealed, the heavy pitting on the pipes was filled with an epoxy-based composite (Belzona 1111). This solution cures at room temperature, so no hot work is involved, and also it offers reduced health and safety risks due to being solvent-free.

Find out more about this application, read the case study below:


Pitting corrosion and bi-metallic corrosion in the HVAC industry

Heat exchangers are commonplace in the Heating, Ventilation and Air Conditioning (HVAC) industry. They work by transferring heat from one place to another. Heat exchangers can be found in many different places, usually working to heat or cool buildings or helping engines and machines to work more efficiently.

In a facility in Ontario, Canada operating in the HVAC Industry, a heat exchanger (HEX) was suffering from pitting corrosion and bi-metallic corrosion, which was resulting in leakage.

Severe pitting corrosion to the heat exchanger
Severe pitting and corrosion to the heat exchanger

An epoxy-based composite for metal repair (Belzona 1111) was applied to the surfaces of the tube sheets and end covers to fill any pitting and damage. Next, a ceramic filled epoxy coating designed to provide erosion and corrosion resistance of metal surfaces (Belzona 1321), was applied to the surfaces using a brush. These non-metallic composite materials also stop the galvanic corrosion issues commonly seen in heat exchangers. Due to the solution chosen, the application was able to be carried out without the need for specialist tools.

Completed application providing bi-metallic and pitting corrosion resistance
Completed application providing bi-metallic and pitting corrosion resistance

The multipurpose polymeric coating used in this application will protect the heat exchanger from bi-metallic and pitting corrosion, whilst also providing resistance to a wide range of chemicals.


Belzona’s epoxy solutions repair corroded metals and can also be used as a preventative measure to protect against future corrosion.

Interested in purchasing Belzona’s epoxy-based composites?


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