COMPARISON AMONG ECOLOGICAL PIGMENTS IN ANTICORROSIVE COATINGS

摘要

Protective coatings are usually formulated using a binder, that gives the most of the properties of the dry film thickness, and a inhibitor. This inhibitor could be solid or liquid, colourless or pigmented). Traditionally, inhibitors used in a protective coatings are mainly inorganic, and lead or hexavalent chromium based. Around the world, there is a trend to eliminate lead and chromate products in paints. On the other hand, during the last decade there were some developments in order to substitute the use of heavy metals as corrosion inhibitors in commercial paints. Manufacturers claimed that these products are even better than chromate based paints. Alternative inhibitors used in coatings are also supposed to promote adhesion to the metallic substrate. In this study, an evaluation of anticorrosive performance of four so-called "ecological" inhibitors was carried out by using Salt Fog Cabinet, according to ASTM B-117 standard. Visual and mechanical evaluation was carried out at different time of exposure. Zinc chromate was used as a blank in order to rank the different pigments. Three resins were selected as binders: alkyd, epoxy and polyurethane.