Corrosion behaviour of Zn–Al–Mg coated steel sheet in sodium chloride-containing environment

• Published in: Corrosion science Vol. 51; no. 10; pp. 2355 - 2363
• Main Authors: Schuerz, S., Fleischanderl, M., Luckeneder, G.H., Preis, K., Haunschmied, T., Mori, G., Kneissl, A.C.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-10-2009; Elsevier
• Subjects: A. Alloy; A. Magnesium; A. Metal coatings; A. Zinc; Applied sciences; B. SEM; Corrosion; Corrosion environments; Exact sciences and technology; Metallic coatings; Metals. Metallurgy; Production techniques; Surface treatment; B. SEM; A. Magnesium; A. Metal coatings; A. Alloy; A. Zinc; Zinc base alloys; Scanning electron microscopy; Aluminium base alloys; Aluminium alloy; Steel; Sodium chloride; Surface treatment; Metal coating; Corrosion; Sheet metal; Magnesium alloy
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2009.06.019

Conventional hot-dip galvanised zinc coated (Z) and novel hot-dip galvanised Zn–Al–Mg alloy coated (ZM) steel sheet samples with a coating thickness of 7
μm each were exposed to standardised salt spray test and cross-sections of the corrosion samples were analysed by using SEM and EDS. On Z corrosion proceeds very fast and the steel substrate is attacked even after 100
h of exposure. ZM samples showed a different behaviour. The entire metallic ZM coating is converted into a stable, adherent aluminium-rich oxide layer, which protects the steel substrate against corrosive attacks. This layer is the main reason for the enhanced corrosion resistance of the ZM coating in sodium chloride-containing environment.