Anodising is a popular process to protect aluminium, but defects can still occur. Here we explore the most common defects and how you can prevent them.
1. Rough or Uneven Surface
Sometimes the anodised layer appears grainy, dull or inconsistent. This often happens when the aluminium was not properly cleaned before anodising or if the process was interrupted.
2. Colour and Finish Variations
The finish may have uneven tones, fading or patches. Uneven dye absorption or variations in the aluminium’s composition usually cause this. Even minor differences in your preparation can lead to noticeable colour problems.
3. Cracking or Peeling
Cracks or peeling can develop if the anodic layer is too thin or stressed. Hard anodising, by www.poeton.co.uk/surface-treatments/anodising/hard-anodising, for example, which produces a thicker, more durable layer, can be prone to cracking if the aluminium is not handled correctly.
4. Residual Acid on the Surface
Invisible acidic residues can remain after anodising. If not properly rinsed, these residues may cause corrosion or staining later.
5. Thin or Weak Coating
A layer that is too thin does not provide full protection, resulting in scratches and less corrosion resistance over time.
6. Forming a Double Layer
Sometimes an extra anodic layer forms, creating weak spots in the coating. These areas are more likely to wear or peel prematurely because the double layer creates weak points in the anodised surface, reducing its protective qualities over time.
7. Corrosion or Surface Damage
Even after anodising, aluminium can corrode if the layer is damaged or too thin or if it was sealed badly.