Zinc Rich Primer

Definition - What does Zinc Rich Primer mean?

A zinc rich primer is a primer that contains a high percentage of zinc dust and acts sacrificially when in direct contact with steel. Zinc-rich primer is used as a coating to protect steel surfaces and extend the life of surfaces where it is applied. The zinc rich coating provides cathodic protection to metal that is similar to cold galvanizing.

Zinc-rich primers are used by many industries for the protection of steel substrates from corrsoion. They can be used in highways and infrastructure, industrial and automotive applications.

Corrosionpedia explains Zinc Rich Primer

Zinc rich primers provide cathodic protection, whereas regular paints provide it by forming an impermeable barrier between the metal and atmospheric moisture. When a cathodic cell is formed, this 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. This primer provides a backup or additional method of protecting the steel from corrosion under a topcoat of epoxy or urethane paint.

There are two types of zinc primer:

  • Inorganic: Inorganic primers must be applied by spraying. Without using a top coat, this provides better steel protection than non-top-coated organic zinc primers.
  • Organic: Organic zinc primers are normally applied by brush, roller or spray. Without a top coat, they do not protect the steel as well as an inorganic primer. This provides same degree of protection as inorganic primers when the primers are top coated.

Organic zinc primer can be a moisture cured urethane zinc primer. Moisture cured urethane coatings are easily applicable to a surface.

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