Anodising – what is that?
Refinement and protection for aluminium parts
Aluminium reacts with oxygen. Through the reaction, with the oxygen contained in the air, a natural oxide layer is formed. A few nanometres thick, the protective layer covers the surface entirely and does not crack when the material is deformed to a certain degree. This patina protects the aluminium from further oxidation and makes it durable for a long time.
With the anodising process, this natural protective layer is reinforced – the surface of the aluminium is even better protected against environmental influences. This unique surface technology creates an oxidic protective layer in an electrochemical process through anodic oxidation – anodising stands for electrical oxidation of the aluminium.
Aluminium parts that are to be anodised are pre-treated. To obtain an even surface, the light metal is cleaned by degreasing and pickled. This dissolves the natural oxide layer and adhering dirt. Now it can be anodised and possibly coloured. To prevent corrosion-promoting substances from accumulating, the porous oxide layer is finally compacted.
When dyeing, a distinction is made between electrolytic dyeing, where shades ranging from light bronze to brown and black are achieved, and dip dyeing. Here, the different shades and nuances are achieved by dipping the aluminium in organic and inorganic substances – the metallic character of the aluminium is retained in both.
Anodised Aluminium is ideally suited for outdoor applications due to its scratch-resistant surface. The colour is an integral part of the anodised layer; the material is optimally protected against abrasion and chemical influences.