Techniques for assessing the protective properties of chromated conversion coatings—Part II: Galvanized steel

Gilroy, D.; Eddowes, P.J.; Dalrymple, Ian; Madina, Virginia; Seco, F.; Barrio, Andrés del; Parkes, James; Byrne, Michael J.; Byrne, Robert H.; Almeida, E.; Maia, Anabela; Pereira, D.; Bentes, F.L.

doi:10.1016/0026-0576(96)83951-1

Cited by 5 publications

(1 citation statement)

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“…Among conversion coatings, the most used in the last decades were chromate-based conversion coatings [10]. Their efficiency is supposed to be due to the combination of excellent anti-corrosion properties guaranteed by self-healing ability and good adhesion of chromates to polymer coating [11][12]. However, chromates were proved to be genotoxic and carcinogen [13] and since 2006, European legislation tries to tackle hexavalent chromium via Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) and Restriction of the use of certain Hazardous Substances (RoHS) [14].…”

Section: Introductionmentioning

confidence: 99%

New experimental approach for intelligent screening of buried metal/oxide/polymer interfaces via local electrochemistry: Example of undamaged model epoxy-coated Zn alloys

Sanchez

Gillet

Shkirskiy

et al. 2021

Electrochimica Acta

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A new simple experimental approach is proposed for in situ mechanistic studies of the underpaint stability of metal/oxide/polymer interface under immersion. It allows an intelligent screening and fast ranking of conversion coatings on Zn alloys designed for further application of organic coatings. The approach is based on the application of a simple electrochemical aging protocol to the samples preliminary coated with a model epoxy-polymer. The latter is enough thin to allow local electrochemical impedance measurement and stable under this protocol, as revealed by attenuated total reflectance infrared spectroscopy (ATR-IR) and electrochemical impedance spectroscopy (EIS). The interface stability and degradation modes characterization is accessed via combined EIS, local electrochemical impedance spectroscopy and mapping (LEIS and LEIM) and in situ optical imaging.The developed approach allowed to discriminate two Zn alloy substrates, one with intact and another with slightly damaged Cr(III) conversion layer, for which no strong differences in the electrochemical behavior or average surface composition was visible prior to the epoxy-polymer application. The relative stability of two substrates with model thin coating, evaluated in the developed electrochemical test, correlated with the observations obtained for the same substrates coated with thick commercial epoxy primer after 1000 h of immersion. The proposed methodology offers the possibility of a rapid intelligent screening of various formulations of Cr(III)-based surface treatments for Zn based substrates designed for paint applications.

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Section: Introductionmentioning

confidence: 99%