Anodising is an electrochemical process that enhances the surface of a metal by converting it into a durable, corrosion-resistant oxide layer.
The technique of anodising was developed on an industrial scale by British engineers in the early 20th century and is now central to many industries, including marine, aerospace, automotive and military. Across the industrialised world, specialists such as https://www.poeton.co.uk/surface-treatments/anodising/hard-anodising provide this essential service. Here are the four most common types.
Sulphuric Acid Anodising
Widely used and cost-effective, this type of anodising produces a hard, abrasion-resistant surface with a clear finish, making it ideal for applications like military weapons and mechanical parts. Its ability to absorb colour dyes also offers aesthetic versatility.
Hard Anodising
This is a more intensive form of sulphuric acid anodising, creating a thicker, denser oxide layer. It is well-suited for industrial uses where extreme wear resistance is critical, such as gears, valves and pistons. Its robust finish also improves electrical insulation.
Titanium Anodising
Using electric current to modify titanium’s oxide layer, titanium anodising improves corrosion resistance and surface bonding. There are several types, including Type 2 for wear protection and Type 3 for medical part identification, which links it closely to the aerospace and biomedical fields.
Colour Anodising
This process combines durability with decoration. Coloured dyes are embedded into the anodised pores, providing a permanent, scratch-resistant finish that ensures long-lasting vibrancy.
Before the development of anodising, industries were reliant on paint or powder coatings and processes such as galvanisation. Anodising offers more efficient protective and decorative advantages tailored to specific industrial needs and aesthetic preferences.