Artificial patina formation onto copper-based alloys: Chloride and sulphate induced corrosion processes

Carlo, Gabriella Di; Giuliani, Chiara; Riccucci, C.; Pascucci, Marianna; Messina, Elena; Fierro, G.; Lavorgna, Marino; Ingo, G. M.

doi:10.1016/j.apsusc.2017.01.080

Cited by 48 publications

(59 citation statements)

References 27 publications

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“…In the next step the natural patination continues with oxidative dissolution leading to the formation of cupric ions according to Equation (3). The ions react with pollutants in atmosphere and form the green phase of patina.…”

Section: Of 18mentioning

confidence: 99%

“…Chlorides are very stable, but their colour is somewhat bluish compared to brochantite. Common patination processes combine treatment by heating, immersion in solution, exposure in acidic water vapour or the application of acidic pastes [3,5,28].…”

Section: Of 18mentioning

confidence: 99%

“…Patina is a layer consisting of corrosion products formed and retained on the copper surface. The rate of formation, composition and colour of patina is influenced by composition of the atmosphere, the level of air pollution and an alternation of wet and dry cycles [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

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Artificial Patination of Copper and Copper Alloys in Wet Atmosphere with Increased Content of SO2

et al. 2019

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Natural copper patina is usually formed over several decades. This work investigates the possibility of obtaining a stable artificial patina based on brochantite in a more reasonable time. The patination process was based on patina formation from a humid atmosphere containing sulphur dioxide. The studied parameters were humidity (condensation and condensation/drying), sulphur dioxide concentration (4.4–44.3 g·m−3) and surface pre-treatments (grinding, pre-oxidation and pre-patination) prior to the patination process. Samples were evaluated by mass change, digital image analysis, spectrophotometry, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). A resistometric method was employed in order to observe the patina formation continuously during the exposure. Conditions inside the chamber were monitored during the exposure (pH of water and concentration of SO2 in gaseous phase). According to XRD, it was possible to deliberately grow a brochantite patina of reasonable thickness (approx. 30 µm), even within a couple of days of exposure. The drying phase of the condensation cycle increased the homogeneity of the deposited patina. Formation kinetics were the fastest under a condensation/drying cycle, starting with 17.7 g·m−3 sulphur dioxide and decreasing dosing in the cycle, with an electrolyte pH close to 3. The higher sulphur dioxide content above 17.7 g·m−3 forms too aggressive a surface electrolyte, which led to the dissolution of the brochantite. The pre-oxidation of copper surface resulted in a significant improvement of patina homogeneity on the surface.

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Section: Of 18mentioning

confidence: 99%

Section: Of 18mentioning

confidence: 99%

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Artificial Patination of Copper and Copper Alloys in Wet Atmosphere with Increased Content of SO2

et al. 2019

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“…In sample S35, Doge Grimani (Figure ), emerald‐green powdery reaction products have been observed (see Figure , between the letter M and A in the first quadrant of obverse side), which seem to be because of an aggressive corrosion reaction, better known as “bronze disease” for its deleterious and fast kinetics . Although not in the scope of the present study, this observation can be taken as a warning for the responsible of the collection to intervene with appropriate protection and remediation actions.…”

Section: The Samplesmentioning

confidence: 99%

Characterization of the mistura alloy used for Venetian sesino coins: 16th century

et al. 2018

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The information provided by material investigations on ancient coins is interesting in many respects, as concerns the archaeological and historical research.In this study a set of Venetian sesino coins, minted over a period ranging from 1554 until 1605, have been investigated in order to shed light on some aspects of the so-called mistura (mixture) alloy. The widespread diffusion of these relatively low-value coins of the Venetian Republic, commonly used in commercial transactions in the second half of 16th century, also outside the territories of the Republic, makes them an important proxy to be used in the reconstruction of the political and historical events of the period. The specific issue of the actual composition of the mistura alloy is herewith addressed for the first time, using a combined approach based on X-ray fluorescence and X-ray diffraction nondestructively applied to the analysis of the samples. It turns out that the mistura alloy, traditionally regarded as a Cu-Ag two phase alloy, over the latest period of circulation of the sesino coins, was actually made of copper only, still containing minor concentrations of lead, to be regarded as an impurity of the alloy and not as an intentional addition.

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“…The deterioration phenomena lead to the formation of both stable protective and reactive degrading species. Their chemical composition is mainly influenced by the composition of the alloy itself and by the environmental agents that come in contact with the object [1][2][3][4][5]. The corrosion products affect the aesthetical appearance of artworks and can compromise their structural properties [6].…”

Section: Introductionmentioning

confidence: 99%

The synergistic effect of an imidazolium salt and benzotriazole on the protection of bronze surfaces with chitosan-based coatings

et al. 2020

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The class of imidazolium salts contains effective anticorrosion additives for metal substrates. This study evaluated the potential of 1-carboxymethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (HO 2 CC 1 MImNTf 2) for application in cultural heritage, exploring it as anticorrosion additive in chitosan-based coatings for the protection of copperbased alloys. Under accelerated corrosion conditions with HCl vapor, the chitosan coating with HO 2 CC 1 MImNTf 2 was less effective than the one with benzotriazole. The coating with a combination of HO 2 CC 1 MImNTf 2 and benzotriazole resulted in the optimal protective efficacy of the bronze surface, and it also maintained high transparency without changing the bronze appearance.

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Artificial patina formation onto copper-based alloys: Chloride and sulphate induced corrosion processes

Cited by 48 publications

References 27 publications

Artificial Patination of Copper and Copper Alloys in Wet Atmosphere with Increased Content of SO2

Artificial Patination of Copper and Copper Alloys in Wet Atmosphere with Increased Content of SO2

Characterization of the mistura alloy used for Venetian sesino coins: 16th century

The synergistic effect of an imidazolium salt and benzotriazole on the protection of bronze surfaces with chitosan-based coatings

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