| Abstract: | The study of new paint systems that are less harmful to the environment and to man than traditional solvent‐borne systems, but have identical anti‐corrosive characteristics, is an issue of great interest at the present time. The authors of this work have taken advantage of the opportunity to use different natural atmospheres in the Ibero‐American region to study the behaviour of new water‐borne, high‐solids and powder paint systems, with and without pre‐treatment. The study has involved coatings exposure in 7 natural atmospheres and different laboratory accelerated tests. It was completed with scanning electron microscopy (SEM) observations, energy dispersive spectrometry (EDS) analysis, and adhesion, water up‐take and electrochemical measurements. It has been concluded that water‐borne acrylic paint systems incorporating primers pigmented with zinc phosphate and others show deficient behaviour in marine atmospheres, but better behaviour in industrial atmospheres. In marine atmospheres, water‐borne epoxy paint systems, including zinc‐rich primers, together with epoxy and epoxy‐polyurethane high‐solids paint systems, present the most efficient anti‐corrosive behaviour. The coatings obtained with epoxy and epoxy‐polyester powder paints only show good behaviour, when applied on an adequate pre‐treatment, in atmospheres of low to medium corrosivity category (C2‐C3). Finally, the best correlation was observed between the results of natural exposure in marine atmospheres, salt spray and water up‐take measurements. It was not possible to verify good correlation between natural exposure and prohesion, adhesion and electrochemical tests. The latter are highly sensitive to the chemical nature of coatings, and seem to be significantly more useful when comparing coatings with more identical nature. |
