THE CORROSION PROTECTION

Zinc has unique properties and is used in their applications. The predominant use of zinc (50-60%) is the corrosion protection, in particular, galvanized, which is the coating of steel with zinc metal to protect against corrosion. Zinc is a very reactive metal (less reactive than magnesium or aluminum, but more reactive than iron) and it may seem strange that this should be able to protect steel from corrosion that could be imagined that zinc is more vulnerable and need all the protection you can get! However, when atmospheric oxygen reacts with the zinc surface, a very dense and impermeable layer of zinc oxide is formed and it is this physical barrier that protects the surface of zinc further attacks.

An article coated with zinc, such as a highway guardrail, a standard lighting or a garbage bomb galvanized quickly loses its shiny silver redesigned and is dull gray, and this is due to the formation of this oxide layer zinc, which is a natural aging process. The physical barrier of the zinc coating and its surface oxide which protects the steel. The interface between the zinc and steel is not really just a metal directly on one another. The galvanizing process creates a reaction between zinc and steel, means that a zinc-iron compound formed between steel and zinc, and this provides another barrier to corrosion and the unbreakable bond between zinc and steel. Zinc does not flake away from the steel in the way the paint.

There are two main classifications of zinc, zinc-General and continuous galvanizing. In general, galvanized steel post, after cleaning, is immersed in a bath of molten zinc and is then removed and emptied, the zinc coating will soon be fixed and the article can then be processed normally. General galvanizing may be used for large objects, like steel beams and structures as well as small items such as nuts, bolts and washers. Zinc is commonly used in zinc containing a small amount of lead deposited on the bottom of the galvanizing bath, and helps to protect the zinc bath in the attack and provides a surface of the liquid in which all non-iron-zinc compounds can be more easily collected and removed.

Zinc can also be applied as a continuous process of electrolytic zinc, although this process has been used less than a continuous hot dip galvanizing. Zinc can also be injected into the molten steel to provide protection, and this method has been used to protect large structures such as bridges. Probably the protection is not as good as if the parts were galvanized the original production, because the preparation and the application may not be as well-controlled building.

Source: www.impreglon.com/