What Is Zinc Coating?

Although steel and other metals are created to be strong, they all have one thing that affects their overall durability. That is the ability to rust. The process of using zinc oxide to coat thee metals to inhibit corrosion is what zinc galvanizing and coating is all about.

Zinc plating is applied to a metal such as steel to give a decorative finish and corrosive resistance to the product. This process is enhanced further with the use of seals, waxes and lacquers.

The use of zinc as an anti-corrosive agent has a basis in simple chemistry. And it can be explained using the operation of a simple car battery. It is all about anodes and cathodes. Zinc is a metal and so is the steel it adheres to. Electrifying the zinc causes it to adhere to the steel. The reason this is done is to protect the steel from corrosion by offering the other metal, as a sacrifice, so to speak.

The rate of corrosion for zinc is measured by its thickness. The thinner the coating, the more apt to rust the item will be. It actually corrodes at a rate 10-20% slower than steel. This makes it the perfect patsy. The reason for this is the formation of protective films that happen naturally in zinc when exposed to the elements.

Though the rate of corrosion in zinc is clearly about 1/25th of that of steel it also varies. The studies show that even then, the rate of corrosion for zinc as opposed to plain steel is a lot less in certain atmospheres and water conditions. Zinc actually starts out corroding a lot faster but the process slows down very quickly. The protective film and the corrosion are impeded.

An elemental metal, zinc can be combined with copper to form the metal we call brass. Zinc is also a trace element important for the proper production of red blood cells in humans. Zinc can be harmful if the amounts get too high in a person's body. That is why it is never a good idea to put things coated with zinc in your mouth.

When viewing a periodic table you will find it listed as Zn. The atomic number of zinc is 30 and the atomic weight 65.37. Pure Zinc found in nature has a melting point of 788 degrees Fahrenheit or 420 degrees Celsius. The metal is a natural dull gray but can be polished until it emits a silver sheen.

Zinc coating is used in all areas of manufacturing from die cast car parts to steel girders. While only about 5% of the zinc used today is mined in America, you can be sure that all Americans benefit from the wonderful properties that zinc has to offer the industrial world.


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Jonathan is an R&D specialist at steel decking experts D-Mac Industries. Jon studies the endless uses of metal deck in structural engineering applications.