If you are asking with respect to chemistry - Galvanising provides outstanding corrosion performance in a wide variety of environments. The galvanising process creates a durable, abrasion-resistant coating of metallic zinc and zinc-iron alloy layers which are bonded metallurgically to the steel and completely covers the item providing a number of significant advantages.
It provides outstanding toughness, resistance to mechanical damage, slows corrosion to about one sixteenth that of steel and a standard minimum coating thickness is applied even to sharp corners to provide a sound and continuous coating.
Preparation is vital to high-quality galvanising. Fero Galv and Fero Blast work together to ensure the preparation for galvanising is perfect. Epoxies, powder coating and other paints must be removed mechanical cleaning such as shot or sand blasting.
The first cleaning step is caustic cleaning or degreasing in a hot alkali solution to remove contaminates like dirt, grease and oil from the metal surface prior to the galvanising process.
Scale, rust, residual paint and other surface contaminates are removed from the steel by acid cleaning or pickling in hydrochloric acids followed by rinsing.
The acid-cleaned steel is then immersed in a flux solution or zinc ammonium chloride and wetting agents to remove the oxide film, which forms on highly reactive steel surfaces following acid cleaning and prevents further oxidisation. This process also heats the steel to between 60-80 degrees Celsius to prepare it for the high temperatures of hot-dipping in the zinc bath.
The molten zinc is heated to about 450 degrees Celsius. When the steel is immersed in the galvanising bath at a controlled rate, the steel surface is coated by the molten zinc resulting in a reaction between the zinc and the formation of a series of zinc-alloy layers. This process takes about 10-15 mins, longer for larger items, and the resulting zinc-alloy layers are actually harder than the base steel. As the item is removed, again at a controlled rate, the molten zinc solidifies to form the outer zinc coating.
After galvanising, the steelwork is immediately dipped is a quench solution which contains additives to prevent the formation of wet storage staining or "white rust" occurring. This process also cools the steelwork in order to facilitate the efficient movement of steel products. Some products can be air-cooled if required.
Then any remaining excess drips and drags are removed.
This is the definition of galvanized according to Marriam-Webster dictionary
https://www.merriam-webster.com/dictionary/galvanize
