Corrosion Protection of Galvanized Steel by a Thin Hybrid Coating with Zr-Rich Inorganic Matrix and Organic Polymer Beads

Khun, Nay Win; Adhikari, Saikat; Li, Y.Y.; Frankel, G. S.; McGee, J. M.; Smith, Tony; Bammel, Brian D.; Zimmerman, John B.

doi:10.5006/2252

Cited by 13 publications

(17 citation statements)

References 24 publications

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“…Redistribution subject to ECS terms of use (see 34.213.227. 119 Downloaded on 2018-05-10 to IP in more detail. The chemical reactions of the organic phase affect the polymerization and condensation reactions within the coating and consequently affect the coating structure as well as the chemical composition of the surface.…”

Section: Concluding Remarks and Suggestions For Further Workmentioning

confidence: 99%

“…6,[32][33][34]44,49,52,76,77,88,90,91,97,102,105,106,108,112 Coatings with thickness between 100 nm and 600 nm were reported as well, 48,81,94,127 and even in the micrometer thickness range from 1.0 μm up to 6 μm. 30,37,43,59,61,80,119,127 Thickness is related to other parameters such as substrate, pH, time of immersion and stirring, as discussed in Conversion bath parameters and Effect of substrate on coating formation sections.…”

Section: C137mentioning

confidence: 99%

“…119 The curves for coated samples were generally shifted to lower current densities with little change in E corr , indicating protection by simple blocking of the surface (Fig. 10c).…”

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confidence: 99%

“…119 Because ascorbic acid was present, V 5+ could be reduced to V 4+ . 119 The coating containing both CAP and V showed the best corrosion performance in the salt spray chamber.…”

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confidence: 99%

“…119 Because ascorbic acid was present, V 5+ could be reduced to V 4+ . 119 The coating containing both CAP and V showed the best corrosion performance in the salt spray chamber. It was suggested that co-incorporation of CAP and V gave rise to more effective coating inhibition via controlled release of V, and an ability to repair scribes through the coating.…”

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confidence: 99%

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Review—Conversion Coatings Based on Zirconium and/or Titanium

Milošev

Frankel

2018

J. Electrochem. Soc.

156

113

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There is a growing interest in conversion coatings based on titanium and/or zirconium as the result of the health and environmental issues associated with legacy chromate and phosphate conversion coatings. Any alternative technology should be environmentally friendly and cost effective, and also able to achieve comparable corrosion resistance and paint adhesion for ferrous and non-ferrous substrates. Conversion coatings based on titanium or zirconium seem to fulfill many of these requirements and thus offer a great potential for further applications. This literature review summarizes the scientific results in this rapidly growing area of research. Following the description of composition of conversion bath and deposition mechanism, the effects of process parameters for conversion baths such as pH, temperature, immersion time and agitation are presented together with coating characteristics. The effects of the type of substrate and substrate pre-treatment are explored for the most-studied substrates: Al alloys, zinc-coated steels and steels. Properties such as composition, morphology and thickness are summarized. The corrosion performance of the conversion coatings is discussed, as well as adhesion of organic coatings and delamination mechanism for a full coating system including substrate/coating/top-coat. Metals used in the construction of products and facilities in most applications, including industrial, infrastructure, transportation, construction, consumer goods, etc., are primarily selected from three groups: steels, zinc-coated (galvanized) steels, and aluminum alloys (AA).1 All of these materials require protection to prevent environmental degradation, and the most common approach to protection against corrosion is a multilayer coating system. Metal components are treated by a series of processes to create this coating system: cleaning, surface pre-treatment, and application of organic coating layers including primer and topcoat. Surface pre-treatments include anodizing (for aluminum alloys) and conversion coatings, which are the focus of this review. Conversion coatings are formed by immersion of a component in a chemical bath and reaction of the metal substrate with the components in the bath to form a layer that coats the surface. These layers provide some corrosion protection by acting as a barrier to the environment or releasing corrosion-inhibiting species. However, their primary role is to improve the adhesion of subsequently applied paint layers.The most important conversion coatings used for corrosion protection and adhesion promotion of ferrous and non-ferrous metal substrates are chromate conversion coatings (CCCs) and phosphate coatings. CCCs are highly corrosion protective. They consist of a backbone of chromium oxide/hydroxide with Cr in the 3+ oxidation state and also contain compounds with Cr in the 6+ oxidation state. 2-5The Cr(VI) provides the characteristic of self-healing, which is the ability to reform a protective coating after it has been breached by a mechanical or chemical proces...

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Section: Concluding Remarks and Suggestions For Further Workmentioning

confidence: 99%

Section: C137mentioning

confidence: 99%

“…119 The curves for coated samples were generally shifted to lower current densities with little change in E corr , indicating protection by simple blocking of the surface (Fig. 10c).…”

mentioning

confidence: 99%

“…119 Because ascorbic acid was present, V 5+ could be reduced to V 4+ . 119 The coating containing both CAP and V showed the best corrosion performance in the salt spray chamber.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

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