The degradation of zinc coatings in salty atmospheres
1989; Elsevier BV; Volume: 17; Issue: 2 Linguagem: Inglês
10.1016/0033-0655(89)80022-6
ISSN1873-331X
AutoresE. Almeida, D. Pereira, Olinto Barbosa Figueiredo,
Tópico(s)Concrete Corrosion and Durability
ResumoSeveral zinc coatings (hot dip galvanized, zinc metallized, organic- and inorganic-zinc-rich primers) were exposed in a salt spray cabinet and in a natural marine atmosphere. No correlation could be found between the behaviour of coatings exposed to these environments. In the present work, the origin of this discrepancy is critically evaluated. The surface degradation of zinc coatings was studied by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS). Corrosion products were investigated using X-ray diffraction. The kinetics of formation and the morphological characteristics of the corrosion product layers were seen to differ in the environments considered. It was concluded that laboratory salt spray testing is not a reliable method for the selection of protective zinc coatings.
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