Electro-galvanised surfaces are usually passivated after galvanising to minimise the oxidation of zinc. Passivation substantially improves both the corrosion resistance and the appearance after galvanising. We have modern zinc passivation processes that meet the following requirements and directives:
Blue Passivation
Blue passivation, or blue chromating, produces a shiny, slightly blue, almost chrome-coloured surface on the electro-galvanised part. Thanks to its low cost, blue passivation can also be used as a good adhesion coating for paint, which also improves corrosion resistance. The blue passivated surface has a very finished appearance and is ideal for interior structures and visible parts. The blue passivation method we use is also RoHS compliant.
Black passivation
Black passivation, or black chromating, gives a zinc-iron coated piece a clean, shiny black appearance. Black passivation is particularly recommended for applications where very good corrosion protection is required. Black passivated articles are now also RoHS compliant. The black-passivated surface has a very finished look and is suitable as a replacement for a painted piece in many cases. Black passivation is done on a zinc-iron coating, which gives very good corrosion resistance.
Thick film passivation or yellow passivation
Yellow passivation, or yellow chromating, produces a gold-yellow corrosion-resistant layer on the surface of a galvanised piece. Traditional yellow passivation has been replaced by environmentally friendly methods that comply with the RoHS Directive. Thick film passivation produces a yellow-tinted non-iridescent surface, unlike traditional 6-carat chromium passivation, which reflects rainbow shades. However, even with the new type of thick-film passivation, the corrosion resistance is excellent.
Thanks to our expertise and modern machinery, passivation can be carried out cost-effectively, whatever the size of the batch. Contact us and together we will find out which method is best suited to your pieces.
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