Corrugated roofing and siding is popular with homeowners and businesses alike, thanks to beneficial attributes such as long life, easy installation, and low maintenance requirements. Most corrugated products are made from galvanized steel. Galvanization is the process of applying a thin layer of zinc on the surface of the metal to protect it from rust (oxidization) and corrosion.
Zinc weathers at a very slow rate, so the coating generally has a long life. Zinc has a greater electro-negativity than iron and hence provides cathodic (or sacrificial) protection to the steel.
This results in the zinc corroding in preference to the steel if the coating is chipped or damaged to expose the base metal.
Besides acting as galvanic protector, The other functions of the zinc layer are as follow:
To retain the steel intact with its full initial strength.
To provide the surface a more pleasing appearance.
To increase the life of any suitable organic finishing system applied over it.
To protect the steel from corrosive attack in most atmospheres, acting as a continuous and lasting shield between steel and the atmosphere.
