PPGI (Pre-painted Galvanized Iron) is pre-painted galvanized steel, also known as pre-coated steel, coil-coated steel, color-coated steel, etc., usually with a hot-dip galvanized steel substrate. The term is an extension of GI, the traditional abbreviation for Galvanized Iron. Galvanizing protects the base steel by providing cathodic and barrier protection. The paint coating acts as a barrier for the hot-dip galvanized coating, significantly reducing the corrosion rate of zinc.