The atmospheric corrosion mechanism of 55Al-Zn coating on steel

摘要

This paper presents the results of a study aimed at understanding the atmospheric Corrosion mechanism of the 55%Al-Zn coating (Galvalume) on steel and a comparison with the behaviour of galvanized sheets (Sendzimir). Research has been carried out in different types of atmosphere in Spain, Brazil and Portugal. Unlike the galvanized coating, which suffers a generalized attack of its surface, the 55%Al-Zn coating undergoes a localized type of attack which commences in the interdendritic regions of the material. An analysis is also made of the additional protection which may be provided by a chemical passivating treatment applied on both types of coating. © 1997 Elsevier Science Ltd.