Organic Zinc Rich Coating

Definition - What does Organic Zinc Rich Coating mean?

Organic zinc rich coatings act as an anti-corrosive primer for iron and steel materials. These coatings are used to protect steel surfaces and extend the life of surfaces where they are applied. They contain a high percentage of zinc dust that acts sacrificially when in direct contact with iron or steel. The zinc rich coating provides cathodic protection to metal that is similar to cold galvanizing. The binder used in an organic zinc rich coating is often epoxy.

Organic zinc rich coatings are used by many industries to protect steel substrates from corrosion. They are used for industrial, automotive, and highway and infrastructure applications.

Corrosionpedia explains Organic Zinc Rich Coating

Organic zinc rich coatings provide cathodic protection, whereas regular paints protect by forming an impermeable barrier between the metal and atmospheric moisture. When a cathodic cell is formed it protects the steel at the expense of the zinc. Zinc primer also provides some barrier protection to the surface.

Although zinc rich primers can be used as a standalone coating, they are often top coated with a paint or epoxy. These coatings provide a backup or additional method to protect the steel from corrosion under a topcoat of epoxy or urethane paint.

There are two types of zinc rich coatings:

  • Inorganic zinc rich coating (IOZ coatings) – These coatings must be applied by spraying. Without a top coat they provide better steel protection than non-top-coated organic zinc primers.
  • Organic zinc rich coating – These coatings are normally applied by brush, roller or spray. Without a top coat they do not protect the steel as well as an IOZ coating.

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