Comparison of the morphology and corrosion performance of Cr(VI)- and Cr(III)-based conversion coatings on zinc

Zhang, X.; Bos, C. van den; Sloof, W.G.; Hovestad, A.; Terryn, Herman; Wit, J.H.W. de

doi:10.1016/j.surfcoat.2004.12.002

Cited by 133 publications

(74 citation statements)

References 28 publications

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“…Information related to coatings morphology after the coating/drying process is very important since the presence of flaws such as pores and/or other defects could be areas were a localized corrosion of the treated zinc surface starts from its exposure to a given environment [19,[69][70][71][72][73][74][75][76][77][78][79][80][81]. The coatings surface morphology was observed at up to a maximum of 10,000X by SEM.…”

Section: Conversion Layer Characterizationmentioning

confidence: 99%

Characterization and Corrosion Resistance of Galvanized Steel/Passivation Composite/ Polyurethane Paint Systems

Sarli¹,

Elsner²,

Tomachuk³

2014

BJAST

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The corrosion performance of electrogalvanised steel sheets pre-treated with a Cr 3+ or Cr +6 -based conversion layer and then covered with polyurethane-waterborne topcoat paint has been studied. The pre-treated metallic panels were coated with one of the three tested polyurethane (PU) topcoat paints, in which the dispersion type was the formulation variable. The pigment was TiO 2 (rutile) with a PVC value of 10. Before and after the immersion in 0.05 M NaCl (pH 5.70) or 0.1 M Na 2 SO 4 (pH 6.36) solutions, replicates of the different samples were subjected to standardized tests (porosity, gloss and color, hardness, flexibility). During the immersion, blistering and rusting degrees were evaluated through periodical visual inspections, while the coated steel performance was monitored by Electrochemical Impedance Spectroscopy (EIS) measurements. Initial (dry) and final (wet) paint adhesion was also determined. EIS data were interpreted and discussed in terms of the time dependence of the electrical (paint coating) and electrochemical (steel substrate) parameters associated with interfacial processes describing the metal/paint system deterioration. According to the electrochemical properties, visual inspection and Original Research ArticleBritish Journal of Applied Science & Technology, 4(6): 853-878, 2014 854 standardized tests results, it was concluded that the studied polyurethane-based polymeric films applied on pretreated electrogalvanised steel provided a very effective protection against corrosion as a result of their excellent barrier properties.

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Section: Conversion Layer Characterizationmentioning

confidence: 99%

Characterization and Corrosion Resistance of Galvanized Steel/Passivation Composite/ Polyurethane Paint Systems

Sarli¹,

Elsner²,

Tomachuk³

2014

BJAST

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“…19,31,[44][45][46][47][48] It has been reported that the addition of Ce(III) enhances TCP systems against pitting on Al alloys. 49 Due to the fact that Ce(III) has both anodic [16][17][18][19] and cathodic 20 inhibition character, conventional electrochemical methods on Al alloys may be compromised by the intermingled intermetallic structure on alloy surface, resulting in contradictory data depending on electrochemical history. As discussed below (Figure 37), for example, the open circuit potential (OCP) shifts in opposite directions: 1) after step-by-step anodic hardening in Ce(III) (green), implying anodic inhibition and 2) after simple immersion in Ce(III) (orange), which implies a strong cathodic inhibition effect.…”

Section: Anodic Hardening Processmentioning

confidence: 99%

Morphology and Mechanism of Benign Inhibitors

Schaefer¹,

Wang²,

Xin³

2012

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“…Typically, as compared to hexavalent chromium coatings, the trivalent chromium coatings exhibit low corrosion resistance, 14) albeit the addition of other substances into the coating solution results in improved corrosion resistance. 15,16) Chromate materials to be developed should exhibit the following main characteristics:…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Cr(III)-based Conversion Coating Solution to Apply Aluminum Alloys for Improving Anti-corrosion Properties

Shim¹,

Kim²,

Han³

et al. 2016

Journal of the Microelectronics and Packaging Society

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It is imperative to find environment-friendly coatings as an alternative to the currently used hexavalent chromate conversion coatings for the purpose of improving the anti-corrosion properties of aluminum alloys. Hence, in this study, the corrosion properties of a trivalent chromate conversion coating solution are analyzed and measured. Because of the presence of multiple components in trivalent chromate conversion coating solutions, it is difficult to control plating, attributed to their mutual organic relationship. It is of significance to determine the concentrations of the components present in these coatings; hence, qualitative and quantitative analysis is required. The coating solution contained not only an environment-friendly component chromium(III), but also zirconium, fluorine, sulfur, and potassium, in the coating film. These metals are confirmed to produce a film with improved corrosion resistance to form a thin layer. The excellent corrosion resistance for the trivalent chromate solution is attributed to various inorganic and organic additives.

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Comparison of the morphology and corrosion performance of Cr(VI)- and Cr(III)-based conversion coatings on zinc

Cited by 133 publications

References 28 publications

Characterization and Corrosion Resistance of Galvanized Steel/Passivation Composite/ Polyurethane Paint Systems

Characterization and Corrosion Resistance of Galvanized Steel/Passivation Composite/ Polyurethane Paint Systems

Morphology and Mechanism of Benign Inhibitors

Characteristics of Cr(III)-based Conversion Coating Solution to Apply Aluminum Alloys for Improving Anti-corrosion Properties

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