ABSTRACT
Conversion coatings belonging in this group are phosphate, chromate, ox ide, and anodized coatings. These coatings are composed of corrosion products that have been formed artificially by chemical or electrochemical reactions in selected solutions. The corrosion products thus formed build a barrier protection for the substrate metal. This barrier reduces the active surface area on the base metal, thereby delaying the transport of oxidizers and aggressive species. By so
doing, the coating inhibits the formation of corrosion cells. The degree of second ary barrier action depends on the compactness, continuity, and stability of the corrosion product layer.
