Corrosion protective pigments : Their efficiency in organic and waterborne primers

A choice of eight non-chromate commonly used corrosion protective pigments has been tested in polyurethane organic and waterborne primers with the application of diverse physicochemical, corrosion and electrochemical methods. A clear dependency was found between the efficiency of barrier and active pigments on the barrier properties of coatings toward water and ions. For barrier pigments conditions of reduced penetration of water and ions through the coating are more favourable, for active pigments a limited diffusion of water promotes their corrosion protective efficiency. It was also possible to differentiate between efficiency and mechanism of action of single pigments and conclude about the correlation of applied methods.