Zirconia primers for corrosion resistant coatings

Gusmano, G.; Montesperelli, Giampiero; Rapone, M.; Padeletti, G.; Cusmà, A.; Kačiulis, S.; Mezzi, A.; Maggio, R. Di

doi:10.1016/j.surfcoat.2006.10.036

Cited by 92 publications

(46 citation statements)

References 16 publications

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“…81 The majority of Zr/Ti based conversion coatings are in the category of thin coatings, between 10 nm and 50-80 nm. 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%

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: C137mentioning

confidence: 99%

Review—Conversion Coatings Based on Zirconium and/or Titanium

Milošev

Frankel

2018

J. Electrochem. Soc.

156

113

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“…The most interesting candidates for these sophisticated surface coatings are organosilanes [2][3][4][5][6], lighter rare earth metals [7,8] and transitional metals [9], respectively. Moreover, promising alternatives are the application of zirconium containing layers on the metal surface by the solgel process [10][11][12][13] or by immersion in hexafluorozirconic acid (H 2 ZrF 6 ) conversion solution [14][15][16][17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Formation and characterization of Fe3+-/Cu2+-modified zirconium oxide conversion layers on zinc alloy coated steel sheets

Lostak

Krebs

Maljusch

et al. 2013

Electrochimica Acta

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Please cite this article as: T. Lostak, S. Krebs, A. Maljusch, T. Gothe, M. Giza, M. Kimpel, J. Flock, S. Schulz, Formation and characterization of Fe 3+ -/Cu 2+ -modified zirconium oxide conversion layers on zinc alloy coated steel sheets, Electrochimica Acta (2013), http://dx. AbstractZirconium oxide conversion layers are considered as environmentally friendly alternatives replacing chromate-based passivation layers in the coil-coating industry. Based on excellent electronic barrier properties they provide an effective corrosion protection of the metallic substrate. In this work, thin layers were grown on HDG-steel-substrates by increasing the local pH at the surface and were characterized using potentiodynamic polarization technique.The influence of Cu(NO 3 ) 2 3H 2 O or Fe(NO 3 ) 3 9H 2 O on morphology and thickness of deposited protective layers were investigated by XPS, ToF-SIMS and FE-SEM. A significant film thickness increase was found by adding Cu 2+ or Fe 3+ ions to the conversion solution. In addition, growth kinetics were studied by in-situ measurements of corrosion potential using potentiodynamic polarization technique.

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“…Moreover, the thickness of the nano-Zr film is on the nanometers order [19,20]. The immersion time is an important parameter that can modify the formation of the converted coating and its microstructure.…”

Section: Resultsmentioning

confidence: 99%

Corrosion Behavior of a Conversion Coating Based on Zirconium and Colorants on Galvanized Steel by Electrodeposition

Costa¹,

Agnoli²,

Ferreira³

2015

TMM

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Corrosion performance of Zr-based coating on substrates obtained by zinc electrodeposition in an alkaline bath is compared to chromate coatings (Cr III and Cr VI). The "nano Zr" is a conversion coating formed by immersion in a hexafluorozirconic acid solution. Since the "nano Zr" coating is transparent, the addiction of a colorant provides color to the surface. In this case, the colorant, when applied after the conversion coating, conferred the yellow color to the surface. The coating produced improves the corrosion protection of the substrate. For this study the samples were analyzed by electrochemical impedance spectroscopy (EIS) and accelerated corrosion test in a humidity chamber. The results showed similar behaviors between the "nano Zr", colorant and the chromate (Cr III) coating. Therefore this kind of conversion coating is a promising substitute for chromate coatings. Keywords: Nano Zr; Immersion process; Electrodeposited zinc; Hexafluorozirconic alkaline solution. COMPORTAMENTO DA CORROSÃO DE UM REVESTIMENTO DE CONVERSÃO À BASE DE ZIRCÔNIO E CORANTES NO AÇO ZINCADO POR ELETRODEPOSIÇÃO ResumoNo presente estudo, avaliou-se o desempenho de revestimentos à base de zircônio e corante sobre substratos de zinco obtidos por eletrodeposição em meio alcalino, em relação aos revestimentos de cromato (CrIII e CrVI). O revestimento "nano Zr" é obtido através da imersão em solução de conversão à base de ácido hexafluorzircônio. Uma vez que o revestimento "nano Zr" é transparente, a adição de um corante proporciona cor à superfície. Neste caso, o corante, quando aplicado depois do revestimento de conversão, confere cor amarela à superfície. O revestimento produzido melhora a proteção contra a corrosão do substrato. Para este estudo ensaios de espectroscopia de impedância eletroquímica (EIS) e testes em câmara úmida foram feitos. Os resultados mostraram comportamentos semelhantes entre o "Zr nano" e corante e o revestimento cromato (CrIII). Por conseguinte, este tipo de revestimento de conversão é um promissor substituto para os revestimentos de cromatização. Palavras-chave: Nano Zr; Processo de imersão; Zinco eletrodepositado; Solução ácida de hexaflúorzircônio.

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Zirconia primers for corrosion resistant coatings

Cited by 92 publications

References 16 publications

Review—Conversion Coatings Based on Zirconium and/or Titanium

Review—Conversion Coatings Based on Zirconium and/or Titanium

Formation and characterization of Fe3+-/Cu2+-modified zirconium oxide conversion layers on zinc alloy coated steel sheets

Corrosion Behavior of a Conversion Coating Based on Zirconium and Colorants on Galvanized Steel by Electrodeposition

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