3 Ways to Remove Oxidation From Aluminium

No manufacturer wants to see oxidised aluminium—it’s an unfortunate discolouration that signifies future corrosion. For example, if an aluminium sheet metal manufacturer has products that are exposed to a humid environment, oxidation or corrosion can be a costly issue. Oxygen in the air reacts with the aluminium, forming a thin layer of aluminium oxide on the exposed areas. This oxide layer is not visible to the naked eye but can weaken the surface and compromise the quality of the aluminium sheets.
Luckily, three aluminium oxidation removal processes are available for various applications and industries. This blog will review the basics of aluminium oxidation, what aluminium is, why it oxidises more than other metals, why oxidation removal matters, and how to remove oxidation from aluminium.

What is Aluminium?

Aluminium is the most common metal on our planet and provides a great deal of functionality. It’s a soft metal that is easily malleable, can withstand heat, and is corrosion-resistant. Pure aluminium is not naturally occurring and wasn’t produced until 1824, but aluminium sulfates and compounds are found in many naturally occurring metals.
Because of its integration with metals, aluminium is found in various items: kitchen utensils, automotive components, gemstones, window frames, air conditioners, and so on. Considering the versatility, it’s likely that you’re in the presence of an aluminium item right now.

What is Aluminium Oxidation?

Aluminium oxidation is the beginning of aluminium’s corrosion process after bonding with oxygen. Oxidation occurs to protect the aluminium from corroding further. It may appear as a discolouration or as an off-white colour.

Why Remove Aluminium Oxidation?

The two main reasons for removing aluminium oxidation are aesthetics and further corrosion prevention.
As mentioned above, aluminium oxidation creates discolouration or an off-white colour. This colouring may be unappealing to look at because it appears dirty.
For the practical side of removing aluminium oxidation, conducting frequent cleanings prevents your aluminium from oxidising or corroding further. The longer that the aluminium oxidises, the more difficult it will be to remove. The aluminium oxidation will eventually make the aluminium product perform poorly.

How to Remove Oxidation from Aluminium - 3 Methods

1. Chemical Sprays or Soaks
Chemical sprays or soaks are sold at retailers like Amazon, Walmart, or Target and are used for intense oxide removals, such as on automobiles or boats. These sprays are made of hydrofluoric acid, sulphuric acid, and phosphoric acid, which requires more protective gear than DIY methods.
Spray or soak the infected area with the chemicals, scrub, and rinse. Then repeat accordingly. The brand, chemicals, and intensity of aluminium oxidation will determine how long this process takes and specific instructions.
Using chemical sprays or soaks is preferable in low volume settings, especially if the part is an aluminium alloy. These chemicals do not have a reaction with the other metals in the alloy and leave behind a clean finish. For instance, the aerospace industry can benefit from these soaks because of the frequent copper, zinc, and magnesium alloys with aluminium. Additionally, it doesn’t risk creating accidental holes, cavities, or deformities that may affect the functionality of the part, which is possible with sanding.
2. Laser Ablation
Laser ablation, also known as laser cleaning, is an automated method for removing aluminium oxidation. Ablation works by using a powerful laser beam with short pulse frequencies to heat the oxidation to the point of evaporation.
There are different types of lasers used for laser ablation. However, at KEYENCE, we recommend a fibre laser or a hybrid laser because of the power capabilities. Using a laser is an automated process, instead of the manual methods. There isn’t any scrubbing, soaking, or rinsing involved. Instead, the removal process takes a few seconds and is completed in one step.
Laser ablation is ideal for manufacturing operations, and excels with parts smaller than 30cm x 30cm. Laser ablation is unique in that it can target precise areas of oxidation even in hard-to-reach spots of non geometric shaped parts. Medical devices benefit from laser ablation because of the corners and curves that may harvest oxidation.
3. Fine Grit Sandpaper
Fine-grit sandpaper is an effective way to remove oxidation without chemicals or heat. It requires a few steps of cleaning pre and post-sanding. The oxidised aluminium can be sanded off with a sanding machine or by manually sanding the part.
First, use a microfibre towel to get the oxidised aluminium area as clean as possible. Once the area is as clean as possible with the microfibre towel, the area must be washed with soap and water.
Pressurised hoses help make the surface as clean as possible. When the area reaches satisfactory cleanliness, it must be dried again with a microfibre cloth. Now, the surface can be sanded. Starting with 240-320 grit sandpaper, smooth the surface and work your way up to fine grit sandpaper of 800-1,000 grit. Once the aluminium oxidation is removed, use a microfibre cloth to remove the dust and spray it down with a hose. Dry with microfibre and add anti-corrosion polish.
This method is ideal for medium-sized surface areas, like the rim of automotive wheels. However, it may not be best for very small or big areas because of how tedious it is.

Looking to Use Laser Ablation?

At KEYENCE, we specialise in laser ablation with our laser marking machines. The laser markers include features like autofocus, 3-axis control, and integration of CAD data to make the aluminium oxidation removal process quick and easy on any target. From tiny metal tools to large automotive parts, the strength and positioning skills of the hybrid and fibre laser tackle anything.
Ready to see laser aluminium oxide removal in person? Contact KEYENCE to request a demo or discuss any questions!