abstract
The mechanisms of the initial stages of localized corrosion at cut edges were investigated for adhesively bonded Zn (Z) and Zn-Al-Mg (ZM) galvanized steel. The results provided strong evidence for the localized nature of corrosion of galvanized coatings at the cut edges and at the adhesive/zinc interface. In both cases a defined localized corrosion attack on zinc in Z sample was observed. On the contrary, in the case of the ZM specimen both zinc solid solution and eutectics exhibited local corrosion. The local attack at the adhesive/Z(ZM) interface was correlated with an anodic undermining process. It develops near the cut-edge surface and at the buried deep adhesive-zinc interface and results in adhesive disbonding in the buried interface. The electrochemical studies revealed that the corrosion kinetics at the metal cut-edges decreases during immersion, which could be due to formation of corrosion products on both steel and zinc surfaces. (C) 2016 Elsevier Ltd. All rights reserved.
keywords
ZN(MG,AL) COATED STEEL; MECHANISTIC APPROACH; POLYMERIC COATINGS; ZINC; DELAMINATION; RESISTANCE; INHIBITION; ALLOYS; DEFECT; MODEL
subject category
Electrochemistry
authors
Yasakau, KA; Kallip, S; Lisenkov, A; Ferreira, MGS; Zheludkevich, ML
our authors
Aleksey Lisenkov
Researcher
Kiryl Yasakau
Assistant Researcher
Mário Guerreiro Silva Ferreira
Retired Professor
Mikhail Zheludkevich
Invited Principal Researcher
Silvar Kallip
Assistant Researcheracknowledgements
The financial support of a Post-Doctoral grant (ref. SFRH/BPD/80754/2011) of the Portuguese Foundation for Science and Technology (FCT) and