ABSTRACT
In this study, nanocrystalline ZnO (NC ZnO) films are considered as interface layers for polymer/metal bonds consisting of hot-dip galvanised steel (HDG) and epoxy resin. NC ZnO films with a thickness of less than one micrometre were deposited on HDG through hydrothermal deposition from aqueous Zn nitrate/hexamethylenetetramine electrolytes. Furthermore, 3-aminopropylphosphonic acid (APPA) and 3-aminopropyltriethoxysilane (γ-APS) were considered for molecular adhesion-promoting layers. 90°-peel tests of water-saturated epoxy films confirm the improvement of bond strength under humid environments. Electrochemical properties of the thin film coatings analysed by current density potential curves indicate effective inhibition of oxygen reduction and metal alloy dissolution. Scanning Kelvin probe (SKP) measurements confirm that the corrosive delamination of the polymer from the metal substrate is significantly slowed down by the considered surface modifications. The combination of NC ZnO films with APPA as an adhesion promoting molecule showed the best performances.
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Acknowledgements
Additionally, we thankfully acknowledge Nadine Buitkamp (Paderborn University) for the FE-SEM measurements and Dr. Martin Wiesing (Paderborn University) for the XPS measurements.
Disclosure statement
The authors declare no competing financial interests.
Data availability statement
The data that support the findings of this study are available from the authors, Dr. Richard Grothe, Jan Striewe and Dr. Dennis Meinderink upon reasonable request.