Effect of Polarisation Mimicking Cathodic Electrodeposition Coating on Industrially Relevant Metal Substrates with ZrO2‐Based Conversion Coatings

Publisher: John Wiley & Sons Inc

E-ISSN: 2196-0216|3|9|1415-1421

ISSN: 2196-0216

Source: CHEMELECTROCHEM (ELECTRONIC), Vol.3, Iss.9, 2016-09, pp. : 1415-1421

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Abstract

AbstractModern ZrO2‐based conversion coatings were deposited on an aluminium alloy (AA6014), a cold‐rolled steel, a zinc electrogalvanised steel and a Sendzimir zinc hot‐dip galvanised steel. Pretreated substrates were subjected to galvanostatic polarisation in aqueous NaNO3 to mimic deposition conditions of cathodic electrodeposition coatings. No significant structural modification of the conversion coatings was found with Raman or photoluminescence (PL) spectroscopy. After treatment, increased PL indicated an increased number of point defects. Downstream monitoring of dissolved Zr indicated an insignificant totally dissolved fraction of 0.01 % after 5 s of polarisation, which may occur through vacancy‐pair coalescence with concurrent oxide dissolution, as discussed for transpassive dissolution. Overall, the ZrO2 films remained intact after polarisation.