Why surface treat aluminium extrusions? (Topic: 14000)

Surface treatment of aluminium is done of aesthetic and decorative reasons, but also to make the material more corrosion and wear resistant. Aluminium has a very thin , natural oxide layer (0,01ñ0,1 µm) on the surface, but chemical or mechanical attack can destroy this layer. The aluminium surface will then be exposed for corrosion attack. The corrosion resistance and the surface appearance can be improved by various types of surface treatment.

Surface treatment can change the property of the material. In the normal anodising process the melting point of the surface will be increased from 650ƒC to 2000ƒC. With use of anodising the surface hardness of aluminium could be increased from approximately 100 HV to 350 HV , however the properties of the substrate material remain unchanged. See Strength levels, table.