Parameters affecting long‐term performance of painted galvanised steels

The aim of this work was to investigate which parameters affect the long‐term performance of coil coated galvanised steel sheet. Therefore, the paint adhesion and corrosion resistance of selected painted pre‐treated galvanised steel substrates were studied. The systems investigated included chromate‐free pre‐treatments and primers. The polymer coated panels were tested by using: T‐bend, combined cross cut and adhesion, prohesion and QUV‐A tests. The surface energy of the painted panels was determined by contact angle measurements and outdoor testing of the panels was also initiated. The test results showed that the primer was the most important parameter for painted metal alloy coated steel, but the long‐term performance of the system also depends on the compatibility of all four layers, i.e. substrate, pre‐treatment, primer and topcoat.