How to Prevent Metal Corrosion

Corrosion can have a variety of negative impacts on metal. When a metal suffers corrosion, it becomes unsafe and unstable, which can ultimately lead to accidents such as collapses. As a result, even minor corrosion requires repair and maintenance. This often results in high overheads for businesses, amounting to approximately $2.2 trillion spent worldwide annually. It is suggested that ‘’25-30%’’ of corrosion effects could be prevented using suitable prevention methods

 

What is corrosion?

Corrosion describes the deterioration of a material due to environmental processes. It is a natural phenomenon that requires three conditions in order to occur: moisture, metallic surface, and an oxidizing agent. The process of corrosion converts the reactive metal surface into a more stable form, typically: it’s oxide, hydroxide, or sulfide forms.

The purpose of this article is to highlight the ways in which a business and its people can go about preventing the dangers of corrosion and extending the life of their projects.

 

Steps to Preventing Corrosion

1.      Metal Type:

One of the most effective ways of preventing corrosion, is to buy corrosive resistant metals, such as: aluminium or stainless steel. Depending on the application, these metals can be used to reduce the need for additional corrosion protection.

 

2.      Protective Coatings:

The application of a paint coating or powder coating is a cost-effective means of preventing corrosion. Paint coatings act as a barrier to prevent the transfer of electrochemical charge from the corrosive agent to the metal underneath.

Another preventative option is to apply a powder coating to the metal. Once applied, the metal is then heated, which fuses the powder into a smooth unbroken film.

3.      Environmental Measures:

As mentioned previously, a lot of corrosion (such as rust), occurs when a metal reacts with the gases in its surrounding environment. By controlling this environment, these reactions are minimized. This can be done in a variety of ways, depending on the contextual factors impacting the metal and its environment. A simple way of reduction would be to reduce the metal’s exposure to rain and seawater – or alternatively, controlling the amounts of sulfur, chlorine, or oxygen in the surrounding environment.

 

4.      Sacrificial Coatings:

Sacrificial coating involves covering the metal with an additional metal type that is more likely to oxidize. There are two main techniques for achieving sacrificial coating: Cathodic Protection and Anodic Protection.

 

Cathodic Protection:

Galvanizing is the most common form of cathodic protection. It involves coating an iron alloy steel with zinc, which is a more active metal than steel – oxidizing as it corrodes, whilst ultimately inhibiting the corrosion of the steel underneath. Cathodic protection is used for steel pipelines carrying water or fuel, water heater tanks, ship hulls, and offshore oil platforms.

 

Anodic Protection:

Anodic protection involves coating an iron steel alloy with a less active metal, such as tin. Tin will not corrode; allowing the steel superior protection so long as the tin coating is in its place. Anodic protection is often applied to carbon steel storage tanks used to store sulfuric acid and 50% caustic soda. Cathodic protection is not suitable for these environments due to the extremely high current requirements.

 

 

5.      Corrosion Inhibitors:

Corrosion inhibitors are chemicals that react with the surface of a metal or its surrounding gasses in order to suppress the electrochemical reactions that lead to corrosion. They are applied to the surface of a metal to form a protective film. To apply them, requires a dispersion technique known as ‘passivation’.

In passivation: a light coat of a protective material – such as metal oxide – creates a protective layer over the metal that acts as a barrier against corrosion. The layer is formed as factors such as environmental PH, temperature, and surrounding chemical composition react with it. Corrosion inhibitors are normally used for petroleum refining, chemical production, and water treatment works.

 

6.      Design Modification:

Design modifications can help to reduce corrosion and improve the resilience of any existing protective coatings. Ideally, a product should be designed, so that it: avoids trapping dust and water, encourages movement of air, and avoids open crevices. Ensuring that the metal is accessible for regular maintenance will also dramatically increase longevity.

 

As highlighted in this article, there are numerous ways in which a company can inhibit the damaging effects of corrosion. Not all the methods mentioned above are cost-effective for a business.  Many of the steps can be avoided if the company was to use the appropriate materials in the first place; that have been designed well, and made of corrosive resistant metals such as aluminium, stainless steel, and powdered metals.

If you are on the lookout for quality materials that have been tested for over 30 years, have a fast response time AND next day delivery – then look no further, as Aluminium Online has one of the most comprehensive ranges of aluminium sections available anywhere in the country. Aluminium Online sells all forms of corrosive resistant products, such as: aluminium angle, round tubes, box sections, and much more!

aluminium channel pipes

 

 

For more information regarding our aluminium products, blog, or contact information, please get in touch today.

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