Duplex coatings
Typically a galvanized coating on its own will provide adequate corrosion protection. Duplex coatings, however, can provide benefits in certain specific circumstances.
Organic coatings may be applied over the galvanized finish for a number of reasons, such as to add colour for improved aesthetics, to try and blend the structure into its surroundings, to try and make the structure stand out from its surroundings or to provide additional corrosion protection in a very severe environment.Â
A duplex coating system offers a number of advantages over utilising just one of the chosen coatings.Â
However, by applying the product over a galvanized coating, a high level of underlying corrosion protection is provided such that if the organic system becomes damaged there is no urgency to conduct immediate remedial work as the galvanized coating will prevent the formation of red rust.
The red rust would otherwise undercut the organic system if applied directly on to a steel substrate.
What is a duplex coating
A duplex coating is defined as a combination of two different coating systems which often complement one another. Typically this means a metallic coating overcoated by an organic system. Examples of such systems are hot dip galvanizing surfaces which have been painted or powder coated.
This datasheet offers information on the following:Â
- various benefits of a duplex system
- specification of the different components of a duplex system
- surface preparation for duplex coatings
