Prolonged protection, by zirconium conversion coatings, of AlSi7Mg0.3 aluminium alloy in chloride solution

Šekularac, Gavrilo; Kovač, Janez; Milošev, Ingrid

doi:10.1016/j.corsci.2020.108615

Cited by 34 publications

(39 citation statements)

References 61 publications

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“…As the contribution of fluorine has been measured to be between 2–3%, and even less for Raw and Bare substrates, it has been considered to not interfere significantly in the interpretation of the results regarding the main components. The EAD coating composition found was consistent with that reported for DC method [ 25 , 35 , 42 ]. In AA1100 samples, the Al-rich and Zr-rich zones pointed out in Figure 2 e, are not differentiated.…”

Section: Resultssupporting

confidence: 89%

“…Taking into account the deconvolution of Zr high resolution spectrum, with two peaks of Zr 3d 5/2 and Zr 3d 3/2 at binding energies of 182.5 eV and 185 eV ( Figure 4 ), respectively, the inorganic coating is mainly composed by zirconium oxide, whereas some minor residual fluorine complexes are probably present [ 17 , 25 , 42 ]. Fluorine element observed in EAD samples ( Figure S3 ) most arises from the bath, whereas that detected in Raw and Bare substrates comes from some equipment contamination.…”

Section: Resultsmentioning

confidence: 99%

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Green Nanocoatings Based on the Deposition of Zirconium Oxide: The Role of the Substrate

et al. 2021

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Herein, the influence of the substrate in the formation of zirconium oxide monolayer, from an aqueous hexafluorozirconic acid solution, by chemical conversion and by electro-assisted deposition, has been approached. The nanoscale dimensions of the ZrO2 film is affected by the substrate nature and roughness. This study evidenced that the mechanism of Zr-EAD is dependent on the potential applied and on the substrate composition, whereas conversion coating is uniquely dependent on the adsorption reaction time. The zirconium oxide based nanofilms were more homogenous in AA2024 substrates if compared to pure Al grade (AA1100). It was justified by the high content of Cu alloying element present in the grain boundaries of the latter. Such intermetallic active sites favor the obtaining of ZrO2 films, as demonstrated by XPS and AFM results. From a mechanistic point of view, the electrochemical reactions take place simultaneously with the conventional chemical conversion process driven by ions diffusion. Such findings will bring new perspectives for the generation of controlled oxide coatings in modified electrodes used, as for example, in the construction of battery cells; in automotive and in aerospace industries, to replace micrometric layers of zinc phosphate by light-weight zirconium oxide nanometric ones. This study is particularly addressed for the reduction of industrial waste by applying green bath solutions without the need of auxiliary compounds and using lightweight ceramic materials.

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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Green Nanocoatings Based on the Deposition of Zirconium Oxide: The Role of the Substrate

et al. 2021

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“…Finally, another interesting strategy to obtain prolonged protection is based on the use of a pre-treatment of a metal during its preparation, the chemical conversion coating being a good alternative for this purpose. In [109] zirconium conversion coatings (ZrCC) have been prepared onto aluminum alloy AlSi7Mg0.3 by immersion of the latter in 100-500 ppm baths of hexaflurozirconic acid (H 2 ZrF 6 ). The experimental results have revealed that ZCC formed from 200 ppm H 2 ZrF 6 bath (pH = 4.8) with a conversion time of 10 min at room temperature has shown the best corrosion resistance.…”

Section: Corrosion Resistance Of Coatings Obtained By Different Surfamentioning

confidence: 99%

“…Schematic presentation of the self-sealing mechanism of zirconium conversion coating applied on AlSi7Mg0.3 during its immersion in 0.5 M NaCl solution. Reprinted with permission of[109].…”

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confidence: 99%

Corrosion of Cast Aluminum Alloys: A Review

Labari

Biezma

Rivero

2020

Metals

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Research on corrosion resistance of cast aluminum alloys is reviewed in this article. The effect of the main microstructural features of cast aluminum alloys such as secondary dendrite arm spacing (SDAS), eutectic silicon morphology, grain size, macrosegregation, microsegregation, and intermetallic compounds is discussed. Moreover, the corrosion resistance of cast aluminum alloys obtained by modern manufacturing processes such as semi-solid and additive manufacturing are analyzed. Finally, the protective effects provided by different coatings on the aluminum cast alloys—such as anodized, plasma electrolytic oxidation (PEO), and laser—is reviewed. Some conclusions and future guidelines for future works are proposed.

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“…They also applied the same strategy to galvanized steel substrates, proving that the Zr-CCC deposition is highly dependent on the solution pH and on the reaction time [20]. Such pre-treatments have demonstrated to improve both the corrosion resistance and the adhesion of top coats and adhesives [9,10,[21][22][23][24]. There are several metals that were approached, such as carbon and galvanized steel [25][26][27], zinc [28], magnesium [29] and aluminum surfaces [13,30,31].…”

Section: Introductionmentioning

confidence: 99%

Aluminum Protection by Using Green Zirconium Oxide Layer and Organic Coating: An Efficient and Adherent Dual System

et al. 2021

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In this work, the use of ZrO2 nanocoating in aluminum substrates, generated by controlled electrochemical chronoamperometry in hexafluorozirconic acid solutions (H2ZrF6·5H2O), resulted in a lower porous films than that obtained by chemical conversion coating. After the application of an epoxy coating, long-term cyclic immersion corrosion tests and scratch tests proved the superior protection of the dual system and the coating lifespan, thanks to the enhanced adhesion of ZrO2 intermediate layer and the organic coating. As zirconium-based electrolytes are considered more friendly bath if compared to that of other conversion coating processes, like chromating, phosphating or anodizing processes, the study opens new insights to the protection of structural metals in sectors such as automotive, naval and aerospace industries. The main advantages are the employment of lightweight intermediate pre-treatment (nanoscale), compared to conventional ones (microscale), and reduction of waste slurry (electrolyte bath free of additives).

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Prolonged protection, by zirconium conversion coatings, of AlSi7Mg0.3 aluminium alloy in chloride solution

Cited by 34 publications

References 61 publications

Green Nanocoatings Based on the Deposition of Zirconium Oxide: The Role of the Substrate

Green Nanocoatings Based on the Deposition of Zirconium Oxide: The Role of the Substrate

Corrosion of Cast Aluminum Alloys: A Review

Aluminum Protection by Using Green Zirconium Oxide Layer and Organic Coating: An Efficient and Adherent Dual System

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