The Anodising Process

Anodising is a finishing process for aluminium in which the visual appearance of the metal is changed to be aesthetically pleasing. This change is caused by chemical processes refined over more than a century since their invention.

To achieve a beautiful visual appearance that will last for the lifetime of the building, the colours, patterns and textures used need to be:

• Stable
• Durable
• Suited for exterior use

To achieve, this, the aluminium is anodised by the passing of an electrical current from the anode to the cathode. The item to be anodised becomes the anode part of the electrical circuit whilst the cathodes are already in the anodising tank. The electrical current causes oxygen to be released at the anode which combines with the aluminium to form the aluminium oxide. This is known as the anodic film.

The depth of the anodic film is determined by the time in the anodising tank, usually between 15 to 60 minutes, which will create an anodic film thickness of between 5 and 25 microns.

The quality of the anodic film is determined by the temperature and concentration of the electrolyte and the current density applied. The anodic film is of a very porous honeycomb structure and must then be sealed in order to achieve the desired weather resistant properties required to ensure the finish is durable and attractive.

The film produced is porous, hard, transparent and can be coloured using various methods, including:

• Electrocolouring – Anolok™ Bronze & Black
• Combination Colouring - UA Organic Colour
• Interference Colouring – Anolok™ II
• Chemical Milling – Unimill
• Texturing – Unitex
• Polishing – Unipol

With more than 60 years of experience behind us, the team at United Anodisers has mastered the art of anodising and can help you create a stunning bespoke finish for your aluminium.

Want to learn more about our service and the quality of our anodised finishes? Contact us today to get all the information you need.

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