PosMAC (POSCO Magnesium Aluminium alloy Coating) is a zinc-magnesium-aluminum 3-element corrosion-resistant alloy-coated steel sheet, developed by POSCO using its proprietary technology. It has 5-10 times better corrosion resistance than regular hot-dip galvanized steel sheets (GI, GI(H)) with the same amount of coating, and also exhibits superior corrosion resistance in the cross-section.

In addition to its excellent chemical resistance, it has excellent internal ductility and acid/alkali resistance in its flat and processed parts. Its coating layer has high hardness and excellent friction coefficient, resulting in outstanding Galling resistance and workability.

This product is used for applications that require high corrosion resistance, such as solar panel support structures, building exterior and interior materials, air conditioner outdoor units, and automotive components.

Main products:
- PosMAC 1.5: Zn-1.5%Mg-1.5%Al (for automotive and home appliances)
- PosMAC 3.0: Zn-3.0%Mg-2.5%Al (for construction materials)