COMPARATIVE EVALUATION OF SEVERAL EXTERNAL COATINGS FOR OIL TANKS

The external surface of oil tanks is exposed to atmosphere and suffers from wind,rain,sunshine,salt fog and industrial exhaust gas,which may cause severe corrosion of the tanks.To prevent the external surface from atmospheric corrosion and extend the service life of the tanks,various external anti-corrosion coatings,such as alkyl sliver coating,chlorosulphonated polyethylene coating,high chlorinated polyethylene coating,acrylate polyurethane coating and fluorocarbon coating,have been developed and used in China.Since different coatings have different surface properties,coatings are chosen by the designer,consumer or owner of the tanks according to the coating performance and individual project requirement.As the alkyl sliver coatings and chlorosulphonated polyethylene coatings have been eliminated through selection or contest due to their short service life,the comparison here is focused on the current popular coatings in terms of accelerated UV ageing (ASTM G153),salt spraying (ASTM B117),acid or alkaline immersion,surface energy and dirt resistance of the coatings.