Electrochemical properties of corrosion products formed on Zn-Mg, Zn-Al and Zn-Al-Mg coatings in model atmospheric conditions

• The electrochemical properties of corrosion products formed under sodium chloride deposits on zinc coatings alloyed with aluminium and magnesium have been studied using impedance spectroscopy (EIS), scanning Kelvin probe (SKP) and photoluminescence (PL) techniques. The low-energy band gap identified in corrosion products on hot-dip galvanized steel was associated with their higher electric conductivity and efficiency of the rate-controlling oxygen reduction reaction. It was attributed to the presence of ZnO, zincite. The formation of ZnO was hindered by the alloying. The alloyed coatings were covered by more compact layers of corrosion products with lower electric conductivity and better barrier properties.

Nyckelord

atmospheric corrosion

impedance spectroscopy

kelvin probe

photoluminescence

Zn-Al-Mg coating

Aluminum coatings

Coatings

Corrosion

Electric conductivity

Electric conductivity measurement

Electrochemical impedance spectroscopy

Electrochemical properties

Electrolytic reduction

Energy gap

Galvanizing

Magnesium deposits

Probes

Sodium deposits

Spectroscopy

Zinc

Zinc alloys

Zinc chloride

Zinc coatings

Zinc oxide

Atmospheric conditions

Barrier properties

Corrosion products

Hot dip galvanized steels

Oxygen reduction reaction

Scanning Kelvin probes

Aluminum

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