Electrochemical characterization of surfaces of galvanized steels under different exposure conditions using gel electrolytes

• Published in: Materials and corrosion 2024-10, Vol.75 (10), p.1297-1312
• Main Authors: Heyn, Andreas, Meist, Moritz, Michael, Oliver, Babutzka, Martin, Valet, Svenja, Ebell, Gino
• Format: Article
• Language: English
• Subjects: atmospheric exposure; corrosion prediction; Corrosion products; Corrosion rate; Electrochemical analysis; electrochemical measurement; Electrolytes; Galvanized steels; Galvanizing; gel‐electrolyte; protective layer; zinc coating
• ISSN: 0947-5117; 1521-4176
• DOI: 10.1002/maco.202414389

The corrosion behavior of galvanized steels and zinc components under atmospheric exposure depends mostly on the corrosion product‐based cover layer formation under the prevailing conditions. The use of agar‐based gel electrolytes makes it possible to use electrochemical methods to obtain a characteristic value from these cover layers that describe their current and future protective capacity. It is shown here that different states of galvanized steel can be distinguished very well under laboratory conditions and that this method is also suitable for use under practical conditions. Based on the characteristic values and assuming future time of wetness, it is very easy to draw up a forecast for the future corrosion rate, which provides plausible values. Electrochemical measurements on galvanized steel can be carried out more easily on practical components using gel electrolytes and show good agreement with laboratory measurements. The electrochemically determined cover layer resistance is a useful characteristic value for evaluating the current condition and further corrosion progression.