What Does Zinc Silicate Coating Mean?
A zinc silicate coating is a type of coating that gives corrosion protection to surfaces such as steel. As the name implies, this type of coating contains large amounts of zinc metallic dust mixed with a zinc silicate binder, and also contain high-build polysiloxae or a hybrid topcoat and primer made from inorganic zinc.
The use of this type of coating and formulations to achieve steel protection has been well known in the protective coating industry. Almost all of the zinc-based coatings are created with either epoxy resin binders or inorganic silicate.
Zinc silicate coatings are also known as inorganic zinc rich coatings or paints because they usually contain a zinc silicate binder.
Corrosionpedia Explains Zinc Silicate Coating
Two major types of zinc-rich paint or zinc silicate coatings exist in the market, and each varies according to the type of binder used in the production process.
- Inorganic zinc-rich paint typically contains a binder such as zinc silicate.
- Organic zinc-rich paint makes use of urethane, butyl or epoxy.
After the zinc-rich paint is applied to the surface, the binder holds on to the particles of zinc that are connected as well as to the steel surface.
Contact between two dissimilar metals will result in a galvanic cell capable of corrosion when subjected to an electrolyte-rich environment. Zinc particles act as the anode while the steel becomes the cathode in the galvanic cell. The action of the galvanic cell causes the zinc to corrode while guarding the steel from galvanic attack.
Zinc silicate coatings are unique because they offer the best protection to metal surfaces despite scratches, pinholes, voids and other defects. These coatings have the following properties:
- Outstanding mechanical properties capable of resisting impact, scratching and scuffing.
- Heat-resistant to as high as 750°F (398°C).
- Some formulations of zinc-rich paint may be immersed in salt water.
- More difficult to apply compared to other types of coatings due to its porous nature.
Zinc silicate coatings must be applied on a totally clean surface for best results.