Rich Coat primers belong to the family of Zinc Rich Coatings that are applied to protect ferrous surfaces from corrosion. These primarily work as sacrificial cathodic protection products. Because zinc is anodic to steel, these particles corrode first, protecting the ferrous substrate beneath the primer from corrosion.

The product is a powdery zinc oxide that exposes the remaining zinc coating for further oxidation, providing protection continuity. Therefore, zinc-based primers provide sacrificial cathodic protection for the steel substrate.

Reduced zinc epoxy primers have around 55% zinc by weight in the cured primer film, whereas zinc-rich epoxy primers have around 80 to 85% zinc by weight.