1. B-IMPACT project : eco-friendly and non-hazardous coatings for the protection of outdoor bronzesGiulia Masi, Maëlenn Aufray, A. Balbo, E. Bernardi, Maria Chiara Bignozzi, Cristina Chiavari, J. Esvan, Nina Gartner, V. Grassi, Claudie Josse, Tadeja Kosec, Carla Martini, Cecilia Monticelli, Luka Škrlep, W. Sperotto, Erika Švara Fabjan, E. Tedesco, F. Zanotto, Luc Robbiola, 2020, objavljeni znanstveni prispevek na konferenci Povzetek: Application of protective coatings is the most widely used conservation treatment for outdoor bronzes. Eco-friendly and non-hazardous coatings are currently needed for conservation of outdoor bronze monuments. To fulfil this need, the M-ERA.NET European research project B-IMPACT (Bronze-IMproved non-hazardous PAtina CoaTings) aimed at assessing the protectiveness of innovative coatings for historical and modern bronze monuments exposed outdoors.
In this project, two bronze substrates (historical Cu-Sn-Zn-Pb and modern Cu-Si-Mn alloys) were artificially patinated, by acid rain solution using dropping test and by "liver of sulphur" procedure (K2S aqueous solution) to obtain black patina, respectively. Subsequently, the application of several newly developed protective coatings was carried out and their performance was investigated by preliminary electrochemical tests. In the following steps of the work, the assessment of the best-performing coatings was carried out and their performance was compared to Incralac, one of the most widely used protective coatings in conservation practice. A multi-analytical approach was adopted, considering artificial ageing (carried out in representative conditions, including exposure to rain runoff, stagnant rain and UV radiation) and metal release, as well as visual aspect (so as to include aesthetical impact among the coating selection parameters) and morphological and structural evolution of the coated surfaces due to simulated outdoor exposure. Lastly, also the health impact of selected coatings was assessed by occupational hazard tests. The removability and re-applicability of the best-performing coatings were also assessed. The best alternatives to the conventional Incralac exhibited were: (i) fluoroacrylate blended with methacryloxy-propyl-trimethoxy-silane (FA-MS) applied on patinated Cu-Sn-Zn-Pb bronze and (ii) 3-mercapto-propyl-trimethoxysilane (PropS-SH) applied on patinated Cu-Si-Mn bronze.
Ključne besede: bronze, patina, protective coatings, eco-friendly, corrosion, aging
Objavljeno v DiRROS: 01.03.2024; Ogledov: 123; Prenosov: 62
 Celotno besedilo (2,01 MB)
Gradivo ima več datotek! Več... |
2. Efficiency of a corrosion inhibitor on bare, oxidized and real archeological bronze in indoor polluted atmosphere - digital image correlation approachTadeja Kosec, Polonca Ropret, 2021, izvirni znanstveni članek Povzetek: A corrosion inhibitor, tolyl methyl imidazole (TMI), was tested in practice and verified in a polluted in-door atmosphere. Special attention was given to its behavior in indoor storage conditions, where volatileorganic pollutants may cause damage to metal artefacts. Prepared samples of bronze and oxidized bronzewere exposed to acetic acid vapors. Raman analysis showed copper acetate and copper nitrate forma-tion. Suppression of corrosion development following the application of tolyl methyl imidazole (TMI) wasobserved. A simple method based on image analysis for corrosion evaluation was specifically developed.The TMI inhibition action was tested on a Roman archeological object and evaluated after exposure toindoor pollutants.
Ključne besede: bronze, inhibitor, corrosion, Raman
Objavljeno v DiRROS: 20.12.2023; Ogledov: 173; Prenosov: 99
Celotno besedilo (2,09 MB)
Gradivo ima več datotek! Več... |
3. Development of multi-component fluoropolymer based coating on simulated outdoor patina on quaternary bronzeTadeja Kosec, Luka Škrlep, Erika Švara Fabjan, Andrijana Sever Škapin, Giulia Masi, Elena Bernardi, Cristina Chiavari, Claudie Josse, Jerome Esvan, Luc Robbiola, 2019, izvirni znanstveni članek Povzetek: Bronze reacts with oxygen, humidity, and pollutants in the atmosphere so that a patina forms. Natural exposure to an outdoor atmosphere can be simulated and accelerated in order to achieve a patina that mimics outdoor ancient patina. In order to avoid the uncontrolled dissolving of either the natural or artificially formed patina, protection of the patina is needed.
In this study, a multi-component fluoropolymer based coating for the protection of bronze patina was developed. In order to provide various functionalities of the coating (such as the hydrophobicity of the coating surface, obtaining interactions within the coating itself as well as a bronze substrate and inhibiting the corrosion processes), a fluoroacrylate coating with appropriate adhesion promoter was suggested, with and without a silane modified benzotriazole inhibitor. The protective efficiency and durability of the applied coatings were investigated electrochemically using potentiodynamic tests and electrochemical impedance spectroscopy in a simulated acid rain solution. All of the developed coatings showed a significant decrease in the corrosion current density. The self-assembled single layer coating (FA-MS) also showed 100% inhibition efficiency. After ageing the coating remained transparent and did not change by UV exposure and/or thermal cycling. The patina and coating investigations using FIB-SEM and EDX showed that the latter coating (FA-MS) successfully covered the surface of the patinated bronze. The mechanism of the bonding was proposed and supported with the spectroscopic observation of a thin and even coating.
Ključne besede: bronze, patina, fluoropolymer coating, atmospheric corrosion
Objavljeno v DiRROS: 25.10.2023; Ogledov: 341; Prenosov: 182
Celotno besedilo (2,17 MB)
Gradivo ima več datotek! Več... |
4. Corrosion protection of brown and green patinated bronzeTadeja Kosec, Živa Novak, Erika Švara Fabjan, Luka Škrlep, Andrijana Sever Škapin, Polonca Ropret, 2021, izvirni znanstveni članek Povzetek: Bronze surfaces, whether bare or patinated, tend to change when exposed to an outdoor atmosphere. Art made of bronze which is exposed to the outdoors is usually artificially patinated. This patina changes when exposed to rain, especially in polluted rain, where sulphuric, nitric or carbonic acids are present.
In order to gain optimal protection of different patinas and consequently reduce the patina changes over the time different protection systems were developed, tested and tailored. Three types of patina (brown, green sulphate, and green persulphate) were prepared, protected and subsequently studied. The protections were based on two coatings (i) fluoropolymer based coating (FA-MS) and (ii) newly developed fluoropolymer based coating with addition of mercaptopropyl groups, named as alternative fluoropolymer coating (FA-MS-SH). Both the pure patinas applied on bronze surfaces as well as the bare bronze were electrochemically tested, first unprotected and then following the application of two different types of protection. After the protection was applied to the pa- tinas, the change in colour was defined. Different techniques were utilised in order to define the morphology and structure of the patinas, as well as the change in colour following application of the coating. It was shown that a fluoropolymer coating (FA-MS) provided the most efficient protection to bare bronze and the sulphate patina, while a newly proposed alternative fluoropolymer coating (FA-MS-SH) offered good protection to bare and brown patinated bronze. A mechanism for the protection of bare and patinated bronze was suggested.
Ključne besede: bronze, patina, protection
Objavljeno v DiRROS: 17.07.2023; Ogledov: 282; Prenosov: 170
Celotno besedilo (5,46 MB)
Gradivo ima več datotek! Več... |
5. Corrosion and protection of non-patinated, sulphide- and chloride-patinated bronzeŽiva Novak, Tadeja Kosec, 2022, izvirni znanstveni članek Povzetek: The surface of bronze undergoes changes when it is exposed to a polluted atmosphere, and bronze should therefore be protected from this natural deterioration. The most common protective coating currently in use is Incralac, which includes toxic components and is reported to dissolve a few months after application. This work therefore investigates a fluoropolymer-based coating (FA-MS), and compares it to the protection offered by Incralac. Bronze samples (non-patinated, sulphide-patinated or chloride-patinated) were exposed to simulated urban rain for four months. The corrosion products formed were characterised using SEM/EDS and Raman analyses. To study the protection efficiency of the newly developed fluoropolymer coating (FA-MS) and Incralac protection, various electrochemical methods were used: measurements of open circuit potential linear polarisation and potentiodynamic measurements. Findings show that the FA-MS coating provides a protection efficiency of 71 % for chloride-patinated bronze and 99.5 % for sulphide-patinated bronze. Contact angles of the FA-MS samples were higher than those of the unprotected samples or the samples protected by Incralac, indicating better hydrophobic properties of the FA-MS coating.
Ključne besede: bronze, corrosion, SEM/EDS analyses, Raman spectroscopy, electrochemistry, odprti dostop
Objavljeno v DiRROS: 31.05.2023; Ogledov: 319; Prenosov: 118
Celotno besedilo (1,30 MB)
Gradivo ima več datotek! Več... |
6. Exploring the protection mechanism of a combined fluoropolymer coating on sulphide patinated bronzeTadeja Kosec, Živa Novak, Erika Švara Fabjan, Luka Škrlep, Matjaž Finšgar, 2022, izvirni znanstveni članek Povzetek: When bronze or artificially patinated bronze is exposed to an outdoor environment that contains aggressive ions such as sulphates, nitrates, and carbonates, the surface of the bronze changes its appearance due to the formation of corrosion products on the surface. Research is being conducted on versatile protective measures that can be used to protect the surface from these changes. A recently synthesised fluoropolymer-based coating with mercaptopropyl groups, i.e. a 3-component fluoropolymer coating FA-MS-SH (silane-modified poly methylmethacrylate (MS) with added mercaptopropyltrimethoxy silane (SH) and a fluoroacrylate (FA)) was explored in detail in this work where its protective mechanism on sulphide patinated bronze was investigated. Electrochemical tests were conducted on the sulphide patinated bronze with and without the 3-component coating FA-MS-SH. Furthermore, FA, MS and SH alone and various combinations and concentrations of FA-MS were studied in order to determine the protective effect and properties of each component. Colour change and contact angle measurements were also defined. FIB-SEM measurements and GCIB-XPS depth profiles were carried out to study surface bonding with the sulphide patina in detail.
A mechanism for the protection of sulphide patinated bronze was presented through the use of a multianalytical tool approach. It was shown that FA physisorbed on the patinated surface, while MS and blends of the components chemisorbed on the layer of sulphide patinated bronze, also resulting in the surface being efficiently protected from corrosion processes.
Ključne besede: bronze, protection, brown patina, fluoropolymer coating
Objavljeno v DiRROS: 31.05.2023; Ogledov: 323; Prenosov: 186
Celotno besedilo (7,67 MB)
Gradivo ima več datotek! Več... |
7. Properties of the fluoroacrylate and methacryloxypropyl-trimethoxysilane applied to a layer of Cu2O on bronze as either single or multi-component coatingsLuka Škrlep, Tadeja Kosec, Matjaž Finšgar, Andrijana Sever Škapin, Erika Švara Fabjan, 2023, izvirni znanstveni članek Povzetek: Various coatings have been developed and explored to protect bronze surfaces against the uncontrolled formation of different corrosion products when exposed to outdoor environments.
In this research, the surfaces of artificially-formed oxidized bronze patinas (OB), consisting of Cu2O, were covered with either a single-component (fluoroacrylate, FA or methacryloxypropyl-trimethoxysilane, MS) or multi-component (a mixture of FA and MS, FA-MS) fluoropolymer coating and investigated. Variations in the concentration of each component in the coating were studied. Electrochemical tests were performed to determine the corrosion protection efficiency, followed by detailed surface analyses of the OBs, both uncoated and covered with single and multi-component coatings. A variety of investigative methods were used, including focused ion beam scanning electron microscopy (FIB-SEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and time-of-flight secondary ion mass spectrometry (ToF-SIMS).
The coating made from a combination of FA and MS resulted in a very high protection efficiency. Despite the increased hydrophilicity of the single MS component, however, it was shown to efficiently protect the oxidized bronze surface. The FA-MS systems showed high hydrophobicity, but no improvement was measured in the efficiency of the corrosion protection when it was compared to the coating that contained 10% MS. According to XPS and ToF-SIMS imaging, the FA component of the FA-MS coating was not present only on the uppermost surface of the coating but throughout the whole coating, which could affect its corrosion protection efficiency.
Ključne besede: bronze, Cu2O layer on bronze, fluoropolymer coating, protection efficiency, surface spectroscopy
Objavljeno v DiRROS: 30.05.2023; Ogledov: 328; Prenosov: 174
Celotno besedilo (8,49 MB)
Gradivo ima več datotek! Več... |
8. An electrochemical and spectroscopic study of surfaces on bronze sculptures exposed to urban environmentDajana Mikić, Helena Otmačić Ćurković, Tadeja Kosec, Neven Peko, 2021, izvirni znanstveni članek Povzetek: Polluted urban environment enhances dissolution of patina and underlying bronze material of recent and historical bronze sculptures exposed outdoors. In this work, two bronze statues, situated in one of the most polluted Croatian cities, were examined in order to characterize composition of patina and its electrochemical stability. The composition of patina on several positions on each sculpture was determined by EDS, Raman spectroscopy, and FTIR measurements. Electrochemical impedance spectroscopy measurements were conducted in order to evaluate the corrosion stability of both patina and underlying bronze. Results obtained in this work show that the two examined bronze sculptures were covered with patina layer that was mainly composed of copper sulfides and sulphates, which is in accordance with the high concentrations of H2S and SO2 in the atmosphere. However, the variations in the appearance of FTIR and Raman spectra revealed that the amount of each species differed from spot to spot, as well as the fact that other compounds, such as carbonates, were present at some areas. This difference in patina composition was reflected in electrochemical behavior as observed by electrochemical impedance spectroscopy.
Ključne besede: bronze, corrosion, spectroscopy, FTIR, Raman, EIS, open access
Objavljeno v DiRROS: 16.05.2023; Ogledov: 282; Prenosov: 165
Celotno besedilo (4,82 MB)
Gradivo ima več datotek! Več... |
9. Effect of silsesquioxane addition on the protective performance of fluoropolymer coatings for bronze surfacesMohor Mihelčič, Miran Gaberšček, Martina Salzano de Luna, Marino Lavorgna, Chiara Giuliani, Gabriella Di Carlo, Angelja Kjara Surca, 2019, izvirni znanstveni članek Ključne besede: bronze, protective coating, nanocomposite, fluoropolymer, POSS nanoparticle, nanoindentation
Objavljeno v DiRROS: 04.12.2019; Ogledov: 2105; Prenosov: 1403
Celotno besedilo (3,13 MB)
Gradivo ima več datotek! Več... |
10. Influence of silsesquioxane addition on polyurethane-based protective coatings for bronze surfacesMohor Mihelčič, Miran Gaberšček, Gabriella Di Carlo, Chiara Giuliani, Martina Salzano de Luna, Marino Lavorgna, Angelja Kjara Surca, 2019, izvirni znanstveni članek Ključne besede: bronze, polyurethane, protective coating, impedance, infrared spectroscopy
Objavljeno v DiRROS: 16.11.2018; Ogledov: 2825; Prenosov: 1492
Celotno besedilo (4,88 MB)
Gradivo ima več datotek! Več... |
