The Anodising Process In brief

Definitions of Anodising

Anodizing or Anodising is a process used to protect aluminium from abrasion and corrosion and to allow it to be dyed in a wide range of colours.

Anodising is an electro-chemical process which physically alters the surface of the alloy to produce a tough oxide layer on the surface. During the anodising process the oxide layer is at first porous, and at this point it's possible to introduce a coloured dye. 'Porous' in this case refers to the molecular level rather than gaping holes - the dye thus needs to be soluble to penetrate this layer. The porous layer is then 'sealed' by boiling the part in water (which converts the oxide to a different crystalline chemical form) permanently trapping the dye beneath the surface. It should be noted that as the anodised surface is a layer of aluminium oxide, rather than metal, it exhibits a very high resistance to electric current.