Anodising, also known as anodic oxidation, is an irreversible electrochemical process that transforms the surface of a metal by creating a protective oxide layer. Widely used in industry, this treatment protects metals such as aluminium, titanium, zinc and magnesium from corrosion, wear and attack by external agents.
The benefits of anodising
- Corrosion protection: the oxide created by anodising forms a resistant barrier that prevents corrosion of the underlying metal, extending its life.
- Increased hardness: the process increases the surface hardness of the metal, making it more resistant to abrasion and scratches.
- Improved appearance: anodising creates a uniform, porous surface that can be coloured, offering a wide range of finishes.
- A base for colouring: the porosity of the oxide layer allows even, long-lasting colour, ideal for decorative applications.
- Electrical insulation and thermal conductivity: depending on the type of anodising, both electrical insulation and thermal conductivity can be achieved, broadening the applications of the treated metal.
The stages of the anodising process
The anodising process has three main stages:
- Pre-treatment: this preliminary stage prepares the metal surface for anodising. It includes brushing, degreasing, pickling, satin finishing and neutralising, which remove impurities and surface oxides.
- Anodic oxidation: the metal is immersed in an electrolytic bath and an electric current is applied. This triggers a chemical reaction that forms an oxide layer on the surface.
- Finishing: after oxidation, the metal undergoes finishing treatments such as oiling or sealing to further improve its properties and appearance.
Applications of anodising
Anodising is used in many sectors, including:
- Aerospace: aircraft and satellite components require high resistance to corrosion and wear.
- Automotive: car and motorcycle parts benefit from the corrosion protection and appearance of anodising.
- Architecture: aluminium profiles for windows, doors and façades are often anodised for strength and durability.
- Electronics: electronic components require electrical insulation and thermal conductivity.
- Household goods: pans, kitchen utensils and furniture can be anodised for durability and easy cleaning.
Anodising is a versatile, reliable technology for improving the properties of metals, broadening their applications and extending their service life. T.M.G. can supply your components machined and anodised through its network of qualified partners: see our services.