Zinc/AZ coating
The thickness of the coating is the essential guarantee condition for corrosion resistance. The thicker the coating thickness for steel coil, the better the corrosion resistance.
For the Pre Painted Steel Coil with (aluminum) zinc steel as the substrate, the thickness of the coating mainly affects the notch corrosion performance of the Pre Painted Steel Coil. The thinner the substrate and the thicker the zinc layer, the better the corrosion resistance of the notch.
How to choose the paint?
The primary function of the coating is reflected in the visual effect and the protective function. The pigments of the coating can be divided into organic pigments and inorganic pigments. The organic pigments are bright in color. The inorganic pigments are generally light in color, but chemical properties and UV resistance are better than organic pigments.
The most commonly topcoats paint are polyester (PE), silicon-modified polyester (SMP), high durability polyester (HDP), Polyvinylidene fluoride (PVDF).
PE and SMP are economical. HDP and PVDF with long service life.
The epoxy resin should be used for the primer if adhesion and corrosion resistance are emphasized; if flexibility and UV resistance are more concerned, polyurethane primer should be selected.
The effect of coating thickness on service life.
The color steel sheet coating can play a specific anti-corrosion effect. It uses the coating film to isolate the corrosive substances from the outside world. However, because the coating film itself is still microscopically porous, moisture in the air will still penetrate the coating in a small amount, causing the coating to blister and possibly cause the coating film to peel off. For steel plates, the coating (galvanized or aluzinc) has a more significant impact on the life of the steel plate.
The secondary coating is denser than the primary coating for the same coating thickness. As a result, the corrosion resistance is better, and the service life is longer.
