Also known as anodic oxidation, metal anodising is an irreversible electrochemical process that creates a protective oxide layer on the metal surface. The main aim of anodising metals is to protect them from wear over time and from ever-changing weather.
The metal most often treated is clearly aluminium, but other metals also need anodising before being placed on the market, including titanium, zinc and magnesium.
Anodic oxidation of metals: the process
The oxide layer covering the metal surface does not form on its own. For it to form, the metal must react with oxygen during the electrolytic process.
There are three stages of anodising. First comes pre-treatment of the material (brushing, degreasing, pickling, satin finishing, neutralising); the next stage is the actual anodic oxidation, which forms a porous, protective layer on the metal; the final stage is finishing, which involves oiling the metal.
Why anodise metals?
Anodising metals is fundamental for preventing corrosion and abrasion caused by the passage of time, wear through use and exposure to external agents.
It also increases the hardness of the material and provides genuine long-term thermal insulation. After the anodising process, the metal’s appearance can also be improved by applying a layer of colour.