What is anodising and why does it matter? This electrochemical process, also known as anodic oxidation, is irreversible. The part is immersed in an electrolytic solution that creates a protective oxide layer on the metal surface. The aim is to increase the resistance of metals such as aluminium, titanium, zinc and magnesium, protecting them from wear and exposure to external agents.
As well as preventing corrosion and abrasion, anodising improves the hardness and consistency of the treated material. A further advantage is that it helps colours adhere, while also providing electrical insulation and controlled thermal conductivity.
The three stages of the anodising process
To form the protective oxide layer, the metal must react with oxygen during the electrolytic process. The treatment is divided into three main stages:
- Pre-treatment of the metal – includes brushing, degreasing, pickling, satin finishing and neutralising to prepare the surface.
- Anodic oxidation – the metal undergoes the electrolytic process, creating a porous, protective layer.
- Finishing – the process ends with oiling the metal to further improve its resistance and appearance.
At the end of anodising, the metal gains new physical and mechanical properties, with increased long-term hardness and thermal insulation. A colour layer can also be applied to improve the material’s appearance, making it suitable for a range of industrial and decorative applications.