LONG-TERM ATMOSPHERIC CATHODIC PROTECTION OF 55 PERCENT AL-ZN COATINGON STEEL AND ITS COMPARISON WITH GALVANIZED STEEL

This paper presents the results obtained in a 5 year study of the galv anic protection afforded to the base steel by a 55 % Al-Zn* coating a nd its comparison with a galvanized coating in different types of atmo spheres. While both coatings hardly supply cathodic protection (CP) in rural and urban atmospheres, in marine and industrial type atmosphere s they present excellent galvanic performance, which is conditioned on ly by the duration of the anodic material on the steel substrate. This duration is considerably greater in the 55% Al-Zn coating, due to its lower corrosion rate in the atmosphere.