Information about anodising
If you use raw aluminum outside, the oxygen in the air will combine with the aluminum and create a thin coat of aluminum oxide of approximately 0,2 µm. The natural oxidation, which occurs in unprotected and uncontrolled environments, will provide a limited amount of protection as well as giving the aluminum an unattractive dark grey look.
The anodising process is identical to the natural oxidation process, but with this technique it is possible to increase the coating thickness significantly and build up a crystalline layer of aluminum oxide that is up to 100 µm thick. m.
Anodising at A/S HAI Horsens
HAI Horsens has developed many different types of anodising, which ensures that the build-up oxide layer lives up to a variation of specific standards, as well as the client’s expectations.
In principle, there is no such thing as good and bad anodising, but some variations are not suited for every application. For example, there are many types of anodising that is used for corrosion protection and optimal adherence.
HAI’s aluminum oxide is virtually transparent, which is why the metallic look is maintained after the surface treatment. This is a significant difference from most other types of surface treatment.
Structure and colour
When a special structure and colour is desired, it is necessary to add supplementary processes to the surface treatment. There is a high number of options to combine the transparent oxide layer with various structures and colours. These options are described under pre- and subsequent treatment. This means that it is the complete combination of treatments that lead to the desired finish.
The name of the anodising describes the overall process. The specific method can be further described with the assistance of the active acid in use.
The most commonly used method is sulphuric acid anodising. However, methods using acids like oxalic acid, phosphoric acid, boric acid, tartaric acid, chromic acid or unique combinations are also possible.