What is Anodising of Aluminium?

Anodising aluminium is a beneficial process that helps to strengthen and protect the surface of the metal from corrosion, in addition to creating a visually appealing hard-wearing protective coating. There are a variety of finishes that LA Metals can provide, with anodising aluminium being just one of them, to give aluminium products their unique aesthetic as well as providing added protection.

Anodising is an important process to understand. In this blog, we will outline the process of anodising aluminium, how to maintain it and understand the differences between this process and other aluminium finishes.

How anodising works

Anodising is an electrochemical process used to create a protective oxide coating on the surface of the aluminium. This process involves immersing the aluminium in an electrolytic bath, which creates an oxide layer by applying a current through the metal. The electrolytic bath is filled with an acid such as sulfuric acid, which allows an electrical current to anodise the desired surface. However, before the aluminium can be placed in the acid, some steps need to be completed to properly allow for the process to be effective.

Firstly, the aluminium surface must be cleaned which can be achieved by wiping with a non-abrasive cloth, or through glass bead blasting, which removes contaminants, such as grease, and provides the aluminium with a bright or satin finish. Then, the aluminium is treated with some light etching to produce an even, matte surface.

After this pre-treatment is complete, the aluminium can then be submerged into the electrolytic bath of sulfuric acid, while a direct electrical current, is applied to the aluminium, which causes the oxygen ions to bond with the aluminium atoms of the surface of the metal, forming a layer of aluminium oxide.

Before the sealing process takes place, it is also possible to add colour to the anodised aluminium through a process known as electrolytic colouring, which is when a dye of the desired colour is added to the electrolyte solution, which is absorbed by the oxide layer during the anodising process. The resulting colour can be controlled by the type and concentration of the dye that is used. Many popular colours include:

  • Gold
  • Brass
  • Black
  • Brown
  • Bronze

And many more.

The benefits of anodising aluminium

There are a plethora of benefits that come from anodising aluminium. One of the main advantages is that the anodising process provides high-wear resistance to the aluminium making it extremely durable. The anodising process also makes the aluminium corrosion-resistant, so you won’t have to worry about your aluminium achieving a rusted look if it encounters moisture.

As well as its visual appeal, the aluminium oxide doesn’t act like a protective layer, rather it is fully integrated with the aluminium itself – so it won’t chip or peel.

Common applications of anodised aluminium

Anodised aluminium is commonly used in a variety of industries, including, automotive, aerospace and construction, due to its durability, corrosion resistance and aesthetic properties. The features of anodised aluminium offer a distinct visual appeal that many industries desire.

  • Construction – anodised aluminium is used in the construction industry for windows, doors, facades and roofing due to its durability and corrosion resistance.
  • Automotive – anodised aluminium is commonly used for exterior trims, wheels and engine parts due to its resistance to wear and corrosion.
  • Electronics – due to aluminium being lightweight, it can be used in electronic devices such as smartphones, laptops and tablets as the anodising process makes these products look visually attractive.
  • Aerospace – Thanks to the beneficial properties of anodised aluminium, it can be used in the aerospace industry as it is strong, lightweight and extremely resistant to corrosion.

Many other appliances utilise anodised aluminium that are much more commercial – and used in everyday home life. These may include, cookware, sports equipment such as bicycles and decorative items like picture frames, jewellery and sculptures thanks to its attractive appearance.

Maintaining and caring for anodised aluminium

Once the process is complete and you have purchased an anodised aluminium product, will you have to maintain and care for it in the long term?

Although anodised aluminium is more durable and resistant to corrosion then untreated aluminium, it still requires some care and maintenance to sustain its appearance and functionality. This can be achieved relatively easily by regularly cleaning the product with mild soap and water and a soft cloth. However, it is important to avoid using abrasive cleaners that can scratch the surface. Additionally, you can also avoid further scratches by handling the aluminium with care and protecting it from sharp objects.

Another good tip to keep anodised aluminium maintained is to avoid prolonged exposure to sunlight, as extensive exposure can fade or discolour the aluminium.

How does anodised aluminium compare to other finishes?

Aluminium finishing can be made up of several processes, such as polishing and powder coating. All these different types of treatment do offer similar benefits including making the aluminium more durable, hard-wearing and lightweight, in addition to each type offering a unique visual appeal.

Anodising aluminium provides a distinct, shiny satin or silver finish, and with the benefit of being able to add a coloured dye to the process, anodised aluminium can look completely unique and bespoke. The visuality of anodised aluminium is slightly different to other finishes such as polishing which offers a more mirrored aesthetic. Powder coating is quite different, as it does provide a new colour to aluminium but without the shiny visual appeal.

Is anodising the right choice for your aluminium products?

If you are looking for a durable, highly insulated, corrosion-resistant aluminium product with a superior appearance, then get in touch with LA Metals as we can anodise a wide range of aluminium products, including 6063T6 items for a variety of businesses and industries.

Contact us today for all your queries answered by calling us on 0121 553 6846 or email at sales@lametals.co.uk.