Long-term atmospheric cathodic protection of 55 % Al-Zn coating on steel and its comparison with galvanized steel

Abstract

This paper presents the results obtained in a 5 year study of the galvanic protection afforded to the base steel by a 55 % Al-Zn** coating and its comparison with a galvanized coating in different types of atmospheres. While both coatings hardly supply cathodic protection (CP) in rural and urban atmospheres, in marine and industrial type atmospheres they present excellent galvanic pertormance, which is conditioned only 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.