Cut-edge corrosion study on painted aluminum rich metallic coated steel by scanning vibrating electrode and micro-potentiometric techniques

Alvarez-Pampliega, A.; Lamaka, Sviatlana V.; Taryba, Maryna; Madani, M.; Strycker, Joost De; Tourwe, Els; Ferreira, M.G.S.; Terryn, Herman

doi:10.1016/j.electacta.2011.11.110

Cited by 60 publications

(55 citation statements)

References 32 publications

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“…In summary, pH in anodic sites does not differ significantly amongst all three samples. The values are marginally lower for AlZn0 coating (these values are in line with the previous study of local pH over the metal coating of similar composition), followed by AlZn30Mg4 and slightly higher values of pH 4.8–5.5 are observerd for for AlZn10. Even less significant changes are found in pH over the cathodic sites, Table , with highest pH values of 9.8–10.3 over Mg‐containing AlZn30Mg4.…”

Section: Resultssupporting

confidence: 91%

Corrosion protection of steel cut‐edges by hot‐dip galvanized Al(Zn,Mg) coatings in 1 wt% NaCl: Part I. Experimental study

Долгих

Simillion

Lamaka

et al. 2018

Materials & Corrosion

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Corrosion of AlZnMg coated steel in chloride media is a complicated process, which progress is determined not only by the electrode reactions but also by the local pH and formation of soluble and insoluble corrosion products. In order to adequately describe and predict the corrosion behavior of steel/AlZnMg cut‐edge, a multi‐ion transport, and reaction model (MITReM) is built. Such model takes into account the transport of species in the solution together with their production/consumption in electrochemical and chemical reactions. The main aim of this work is the validation of a numerical model for describing and predicting corrosion of steel/AlZnMg cut‐edge in immersed conditions. This first part describes the experimental work done to obtain model input parameters and validation measurements. The metallic coatings are characterized experimentally with respect to their composition and microstructure, global and local electrochemical behavior (polarization curves, AESEC, and SVET). Local distribution of corrosion products and local pH are also characterized. No blocking effect of the precipitated corrosion products has been observed and dedicated measurements are performed to validate this observation. Based on the experimental input from this part, numerical models of cut‐edge corrosion with different levels of details are developed in Part II.

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Section: Resultssupporting

confidence: 91%

Corrosion protection of steel cut‐edges by hot‐dip galvanized Al(Zn,Mg) coatings in 1 wt% NaCl: Part I. Experimental study

Долгих

Simillion

Lamaka

et al. 2018

Materials & Corrosion

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“…The localized corrosion activity occurring over a commercial grade HDG surface immersed in aqueous sodium chloride electrolyte has been mapped using in situ SVET, which has been widely used in previous corrosion studies. [13][14][15][16][17][18][19][20][21][22] The effect of concentration and pH on corrosion inhibition by H 2 PP and an inorganic inhibitor, namely sodium phosphate (Na 3 PO 4 ), are assessed. A pH of 11.5 has been chosen to mimic the underfilm conditions found in a corrosion-driven delamination cell.…”

mentioning

confidence: 99%

Inhibition of Localized Corrosion of Hot Dip Galvanized Steel by Phenylphosphonic Acid

Glover

Williams

2017

J. Electrochem. Soc.

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Phenylphosphonic acid (H 2 PP) is investigated as a corrosion inhibitor of hot dip galvanized steel (HDG) fully immersed in a 5% (w/v) sodium chloride electrolyte. An in-situ Scanning Vibrating Electrode Technique (SVET) is used where concentrations of H 2 PP are systematically added to the electrolyte in neutral conditions. H 2 PP, at a concentration of 5 × 10 −2 mol dm −3 , is shown to effectively inhibit localized corrosion over a 24 h period with 96% efficiency. H 2 PP is compared with a sodium phosphate (Na 3 PO 4 ) inhibitor at the same concentration over a wide pH range. With current legislative pressure to eliminate Cr(vi)-based inhibitors from protective coating formulations, there is a pressing need to identify effective, environmentally-friendly alternatives. Chromatefree passivation treatments have been studied extensively 1-4 and the most widely used alternative to chromate is a phosphate passivating treatment. Such a system facilitates the precipitation of protective zinc compounds via the supply of soluble anions that react with the zinc ions generated in metal dissolution.5 A phosphate passivation treatment generates a Zn 3 (PO 4 ) 2 barrier to inhibit the anodic process, 4,5 the formation of which can act to extend the pH stability of the surface layer down to values of around pH 6. However, as zinc phosphates are 1000 times more soluble than Cr (III), inferior corrosion inhibition performance is observed. 7 The corrosion of a zinc surface generates a wide range of pH zones, whether in bulk electrolyte conditions, atmospheric conditions or, most notably, under a water droplet. 8,9 Corrosion-driven cathodic coating delamination phenomena produces an alkaline underfilm environment where values of pH 10-11.5 have been recorded previously on a coated zinc surface. 10In order to compete with an adsorbed chromium (III) oxide layer, an effective corrosion inhibitor system would have to be stable in a range of pH 4-14.7 It is therefore of great importance to examine potential chromate replacement inhibitors in non-neutral conditions.In a recent Scanning Kelvin probe study, we showed that in-coating additions of H 2 PP increased the initiation time for underfilm cathodic coating delamination by up to 20 h and reduced the delamination rate by up to 94% on hot dip galvanized steel (HDG) surfaces.11 An 'etch' effect was shown to be the dominant inhibition mechanism, whereby a reaction occurs at the point of first contact of the wet coating with the substrate producing an interfacial metal phosphate salt layer. We hypothesize that a second mode of inhibition occurs whereby the leaching of dissociated PP 2− ions from the coating into the substrate/coating interface forms a ZnPP layer, blocking the anodic reaction. H 2 PP has been shown previously to strongly adsorb onto surface oxide films, disfavoring chloride.12 The principal aim of this work is to determine the efficiency of H 2 PP as an inhibitor for HDG surfaces in bulk immersion conditions. The localized corrosion activity occurring over a commercial gr...

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“…Different ways have been applied in literature to obtain the currents from SVET maps, such as observing the maximum value of anodic and cathodic peaks [43] as well as integrating anodic or cathodic currents [29,44,45]. In particular, the latter method can be used to characterize the inhibition efficiency of corrosion inhibitors [29].…”

Section: Analysis Of the Total Anodic And Cathodic Currents From Svetmentioning

confidence: 99%

Study of corrosion inhibition of coupled Al 2 Cu–Al and Al 3 Fe–Al by cerium cinnamate using scanning vibrating electrode technique and scanning ion-selective electrode technique

et al. 2015

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Cut-edge corrosion study on painted aluminum rich metallic coated steel by scanning vibrating electrode and micro-potentiometric techniques

Cited by 60 publications

References 32 publications

Corrosion protection of steel cut‐edges by hot‐dip galvanized Al(Zn,Mg) coatings in 1 wt% NaCl: Part I. Experimental study

Corrosion protection of steel cut‐edges by hot‐dip galvanized Al(Zn,Mg) coatings in 1 wt% NaCl: Part I. Experimental study

Inhibition of Localized Corrosion of Hot Dip Galvanized Steel by Phenylphosphonic Acid

Study of corrosion inhibition of coupled Al 2 Cu–Al and Al 3 Fe–Al by cerium cinnamate using scanning vibrating electrode technique and scanning ion-selective electrode technique

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