Anodising

Anodising

Aluminium item anodised in 4 different colors.

Electrochemical surface treatment, also referred to as anodising, is a process of increasing the natural oxide layer formed on the aluminium surface when it comes in contact with oxygen. 

The oxide layer is increased by means of electrical current, which makes the aluminium surface more durable. It is possible to use anodising for decorative purposes as well since the anodised surface can be dyed. From an aesthetic perspective, anodising preserves the metallic surface of aluminium and makes it appear more uniform.

Below you will find information about the anodising process as well as recommended areas of applications for anodised aluminium in relation to the thickness of the oxide layer.

 

The anodising process

As you can see in the accompanying illustration, an aluminium piece is lowered into an electrolytic bath and current is passed through the electrolytic solution. Aluminium here functions as the anode electrode of an electrical circuit, hence the name anodising. The electrolytic bath forms an oxide film, which, instead of being on the surface of the metal, is incorporated into the aluminium.

 

 

 

The oxide layer thickness determines the application

The different electrolytic bath factors, e.g. temperature, amperage and time, all affect how thick the oxide layer will be. Oxide layer thickness influences the areas of application of the different anodised aluminium pieces:

 

Normal Anodising           
10 µm  Normal stress indoors.                    
15 µm  Hard wear indoors and outdoors in dry and pure air.                 
20 µm  Normal to hard stress outdoors, e.g. in transport and construction. Great stress under chemical influence indoors, e.g. in the food industry.
25 µm  The surface is exposed to great stress in the form of a corrosive environment or wear              

Layer thickness guide

If you are uncertain about how many µ to anodise your surface with or if you have any other questions about the process, our skilled team with their extensive knowledge will be happy to assist you by offering guidance and instructions.

 

Anodising process in pictures:

  • Anodising: Preparing aluminium items
  • Anodising: Pre-treatment
  • Aluminium items being anodised
  • Anodized items