Zinc phosphate (ZP), barium metaborate, and strontium chromate pigments are also common ingredients in corrosion-inhibiting coatings. Thin wash-inhibiting primers are often formulated with chromate or phosphate pigments that are introduced in a synthetic polymeric binder such as a vinyl chloride copolymer. The variety of inorganic corrosion-inhibiting pigments includes also lead carbonate, strontium chromate, zinc oxide, and ZP.
Zinc phosphate (ZP) is the most commercially successful non-toxic inhibitive pigment used in paint formulations. Furthermore, the use of phosphates does not represent an excessive cost, and their application is even easier than other proposed alternatives for chromate pigments. This is the anticorrosive pigment most frequently used in paints. The massive use of nontoxic and environmentally acceptable ZPs developed an immense pressure for regulations that prohibited the use of red lead and chromated anticorrosion pigments. Experimental results suggest that ZP and all phosphate-based pigments (zinc-aluminum polyphosphate, ZP modified with organic corrosion inhibitor, etc.) exhibit improved anticorrosion efficiency when their concentration is increased.
