Zr-based conversion layer on Zn-Al-Mg alloy coated steel sheets : insights into the formation mechanism

Zr-based conversion layers are considered as environmentally friendly alternatives replacing trication phosphatation in the automotive industry. Based on excellent electronic barrier properties they provide an effective corrosion protection of the metallic substrate. In this work, thin protective layers were grown on novel Zn-Al-Mg alloy coated steel sheets by increasing the local pH-value at the sample surface leading to deposition of a Zr-based conversion layer. For this purpose Zn-Al-Mg alloy (ZM) coated steel sheets were treated in an aqueous model conversion solution containing well-defined amounts of hexafluorozirconic acid (H2ZrF6) and characterized after different immersion times with SKPFM and field emission SEM (FE-SEM)/EDX techniques. A deposition mechanism of Zr-based conversion coatings on microstructural heterogeneous Zn-Al-Mg alloy surfaces was proposed.

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Einordnung

Datum der Veröffentlichung:
19.11.2020
URN:
urn:nbn:de:hbz:464-20201119-171929-2
DOI:
10.1016/j.electacta.2014.05.163
Sprache:
Englisch
Ressourcentyp:
Text
Kollektion:
E-Publikationen
Sachgruppen der Deutschen Nationalbibliographie:
540 Chemie
Einrichtung:
Fakultät für Chemie, Anorganische Chemie
Informationen zur Erstveröffentlichung:
This is the Authors Accepted Manuscript of an article published in: Electrochimica Acta 137 (2014) 65-74. Available online 6 June 2014.
The final version may be found at: https://doi.org/10.1016/j.electacta.2014.05.163
Versionskennzeichen:
Authors Accepted Manuscript

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