What Does Zinc Rich Primer Mean?
A zinc rich primer is a chemical substance that contains high concentrations of the silver-white metal zinc. Zinc rich primers are used by many industries as a preparatory coating to protect iron or steel substrates against corrosion.
Corrosionpedia Explains Zinc Rich Primer
Zinc rich primers are unique from regular primers because they contain zinc, and therefore possess highly sacrificial anodic properties. High concentrations of zinc dust act sacrificially when in direct contact with steel by providing cathodic protection and galvanizing properties.
Galvanizing is a corrosion protection process for steel or iron, in which the substrate is coated with zinc to prevent it from rusting. The galvanization process entails immersing a clean, oxide-free iron or steel object into molten zinc, which then forms a zinc coating that is metallurgically bonded to the object's surface.
Unlike regular paints that provide protection by generating an impermeable barrier between the metal and atmospheric moisture, zinc rich primers provide cathodic protection.
There are two types of zinc primers: organic and inorganic. Organic zinc rich primers are often used in the form of a moisture cured urethane zinc primer.