Zinc-rich coatings are coatings that contain a high percentage of zinc dust, which has a sacrificial effect when in direct contact with steel. Zinc-rich coatings are used to protect steel surfaces from corrosion and extend the life of the surface. Zinc-rich coatings provide cathodic protection for metals similar to cold galvanizing.
Many industries use zinc-rich coatings to protect steel substrates from corrosion. They are used in highway and infrastructure, industrial and automotive applications.
Zinc-rich paints provide cathodic protection, while ordinary paints protect by creating an impermeable barrier between the metal and atmospheric moisture. Cathode cells protect steel at the expense of zinc. The zinc coating also provides some barrier protection to the surface.
Although zinc-rich coatings are available as stand-alone coatings, they are usually topped with paint or epoxy. This primer provides an alternate or additional method to protect steel from corrosion under an epoxy or polyurethane paint finish.
There are two types of zinc coatings:
Inorganic: Inorganic zinc coatings require spraying. When not topcoated, inorganic zinc coatings provide better steel protection than untopcoated organic zinc coatings.
Organic: Zinc organic coatings are usually applied by brush, roller or spray. When topcoats are not used, they do not protect the steel like inorganic primers. When the coating is a topcoat, organozinc coatings do provide the same level of protection as inorganic coatings. Organozinc coatings are available as moisture-curing polyurethane zinc primers that are easy to apply to surfaces.
