Choosing the Correct Anodising

The thickness of the anodic layer produced in the anodising process is directly related to its corrosion performance and longevity – the thicker the layer the longer the life. However, this is also linked to the environment in which it will be situated. In coastal and geothermal areas a thicker grade of anodising should be used to minimise any risk of contamination from those environments.

Use Table 1 (below - at the bottom of this page) and the WANZ Corrosion Zone Maps as a guide to your requirements.

 

 

 

Table 1 – Minimum Coating Thickness

NZS 3604 Corrosion Zone		Minimum Thickness Microns	Suggested Thickness Microns
Sea Spray	Typically within 500m of the sea or within 100m of tidal estuaries. Predominantly the West Coast of the South Island the West Coast of the top half of the North Island. This zone also includes all off-shore islands.	25	25
1	Coastal areas that are not deemed “sea spray” but are still close to the coast, this includes almost all of Auckland.	20	25
2	Inland coastal areas that would normally lie between coastal and hill country.	12	20
3	Inland New Zealand, typically hill country where rainfall is plentiful.	12	12
4	Geothermal areas. Other areas to be included in this zone would be: swimming pools, polluted and high corrosion risk areas.	25	25
Notes:
1	All exterior black minimum 20 micron – application specific.	20	25
2	All bright anodised maximum 20 micron to avoid dulling of finish.	12	Application specific