what corroded aluminium looks like

Aluminium is found everywhere, from aeroplane wings to soda cans, and is well-known for its strength and durability. But even it can't escape the one thing every metalworker fears: corrosion.

Aside from being unsightly, corrosion can damage the structural integrity of aluminium enough to make it totally unusable. That's why recognising the telltale signs and implementing preventative measures are key to keeping your aluminium components safe and strong.

Thanks to our decades of experience, the team at Clickmetal know more about aluminium than anyone else. Below, we'll explore what corrosion is, what causes it in aluminium, how to identify its signs, and ways to prevent it. Let's dive in!

What is corrosion?

Corrosion is a natural process that happens when metals react with their environment and start to deteriorate. The most common form of corrosion is oxidation - this is when metals react with oxygen in the air, leading to the formation of metal oxides or other compounds. This process can weaken the material, compromise its structural integrity, and often results in the formation of rust on iron and steel surfaces.

The rate and severity of corrosion depend on the type of material, environmental conditions, and the presence of specific corrosive agents. For example, a metal that's constantly exposed to moisture and salt is more at risk of corrosion than one in a sheltered environment.

Why does aluminium corrode?

Thanks to the formation of a thin, protective oxide layer on its surface, aluminium tends to be more resistant to corrosion than other metals. However, this doesn't make it completely immune.

The most common form of aluminium corrosion is known as pitting corrosion. This happens when localised damage to the protective oxide layer exposes the underlying aluminium to corrosive environments. However, it can also be vulnerable to other types of corrosion depending on the circumstances.

Aluminium is particularly at risk of corrosion when exposed to:

  • Highly acidic or alkaline conditions.
  • Salts, especially chloride ions. This is a common concern in marine environments or areas where de-icing salts are used on roads.
  • Elevated temperatures. This is particularly relevant in industrial settings where aluminium is exposed to high temperatures and corrosive atmospheres.
  • Physical damage to the protective oxide layer, such as scratches or abrasions.
  • A more noble metal (such as copper or stainless steel) in the presence of an electrolyte, leading to galvanic corrosion. This is because aluminium becomes the anode, and the more noble metal becomes the cathode in a galvanic cell.

What does corroded aluminium look like?

Corroded aluminium can appear in a variety of forms, depending on the type of corrosion and the severity of the damage. In some cases, the aluminium may simply be discoloured or pitted. In other cases, the aluminium may be cracked or even crumble. You can get an idea of how it may look in the pictures below.

corrosion of aluminium

This image demonstrates the small, discrete craters typical of pitting corrosion.

aluminium corrosion

The white, chalky substance pictured here is the aluminium oxide on the surface beginning to break down due to corrosion.

aluminium that's corroded

This image shows severe corrosion on an aluminium V-2 T-34 tank engine - note the deteriorated surface, discolouration, and pitting.

How do you prevent corrosion in aluminium?

Preventing corrosion in aluminium involves taking several proactive measures to protect the metal from exposure to corrosive elements. Here are some common methods:

  • Anodising: Anodising is a process that creates a protective oxide layer on the surface of aluminium. This layer enhances corrosion resistance and provides a durable finish.
  • Coatings: Apply protective coatings such as paint, lacquer, or clear sealants to create a barrier between the aluminium and the surrounding environment. High-quality coatings act as a shield against moisture, chemicals, and other corrosive agents.
  • Alloys: Choosing the right aluminium alloy for a specific application can improve corrosion resistance. Certain alloys, such as 5000 and 6000 series, offer better resistance to corrosion than others.
  • Avoid Harsh Environments: Limit exposure to harsh environmental conditions, especially those containing high levels of salt, chemicals, or pollutants. These substances can accelerate the corrosion process.
  • Proper Cleaning: Regularly clean aluminium surfaces to remove accumulated dirt, salt, or other contaminants that may contribute to corrosion. Use a mild detergent and water, avoiding abrasive cleaners.
  • Galvanic Corrosion Prevention: Avoid placing aluminium in direct contact with dissimilar metals to prevent galvanic corrosion. If different metals must be in contact, use insulating materials or apply a protective coating to isolate them.
  • Proper Storage: Store aluminium products in a dry, well-ventilated environment to minimise exposure to moisture. Proper storage helps prevent the onset of corrosion.
  • Regular Maintenance: Conduct routine inspections and maintenance to identify and address any signs of corrosion early on. Prompt repairs or touch-ups can prevent further damage.
  • Cathodic Protection: In some cases, cathodic protection methods, such as sacrificial anodes or impressed current systems, can be employed to protect aluminium structures from corrosion.
  • Control Humidity: Controlling the humidity in indoor environments can also contribute to preventing corrosion. Low humidity levels can reduce the likelihood of moisture-related corrosion.

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Whether you're replacing worn aluminium or diving into a new project, Clickmetal have got you covered. We have a diverse range of aluminium components ready to send out, cut to your specifications and delivered with speed to match your project timeline. Our stock includes:

All components are precision cut, tested to meet rigorous quality control standards, and promptly shipped within 3-5 working days of your order. You'll receive your package via 24-hour courier service, so you can begin work without delay.

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Images from Wikipedia