Rieger Metallveredlung Blog – Anodizing - Anodized aluminum obects
03.08.2022 - Blog


A process for the surface treatment of aluminum

Anodizing is a process for the surface treatment of aluminum, which basically means "electrolytic oxidizing aluminum".

How does the process work?

During the anodic-electrolytic oxidation of aluminum and its alloys, anodic aluminum is transformed into aluminum oxide Al2O3 (a kind of ceramic) with the help of the electric current in the solution of a suitable chemical substance on the surface.

In conventional electroplating, the coating is formed from parts of the electrolytic bath on the surface of the piece to be plated from the outside. Meanwhile, the aluminum oxide is formed and grows only from the inside at the contact zone between the oxide layer and the metallic aluminum. The aluminum is thus captured by the conversion process itself and is continuously transformed in the process. This is why we also speak of a conversion coating. In the process, the coating grows approx. ⅔ into the base material aluminum and approx. ⅓ onto the original surface.

What are the areas of application?

The area of application includes all areas where aluminum and its alloys are to be coated. Be this for decorative, wear and/or corrosion protection reasons, for example in the automotive, electrical and fittings industries.

The advantages of the process

The anodizing process offers numerous advantages. The good adhesion of the anodized layer to the aluminum, good corrosion protection for aluminum and the hardness of the conversion product are just some of the many positive properties. In addition, there is the possibility of colorability with purer aluminum alloys.