CORROSION AND PROTECTION OF NON-PATINATED, SULPHIDE- AND CHLORIDE-PATINATED BRONZE
Keywords:
bronze, corrosion, SEM/EDS analyses, Raman spectroscopy, electrochemistry
Abstract
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.
References
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22. V. Hayez, J. Guillaume, A. Hubin, H. Terryn, Micro-Raman spectroscopy for the study of corrosion products on copper alloys: setting up of a reference database and studying works of art, J. Raman Spectrosc., 35 (2004), 732–738, doi:10.1002/JRS.1194
2. D. MacLeod, Bronze Disease : An Electrochemical Explanation, ICCM Bulletin, 1981, 16–26, doi:10.1179/ICCM.1981.7.1.002
3. D. A. Scott, A Review of Copper Chlorides and Related Salts in Bronze Corrosion and as Painting Pigments, Stud. in Conserv., 45 (2000) 1, 39–53, doi:10.1179/sic.2000.45.1.39
4. L. Robbiola, C. Fiaud, S. Pennec, New model of outdoor bronze corrosion and its implications for conservation, ICOM-CC, 1993, 796–802
5. A. Casanova Municchia, F. Bellatreccia, G. D’Ercoli, S. Lo Mastro, I. Reho, M. A. Ricci, A. Sodo, Characterisation of artificial patinas on bronze sculptures of the Carlo Bilotti Museum (Rome), Appl. Phys. A Mater. Sci. Process., 122 (2016), 1-8, doi:10.1007/S00339-016-0551-4
6. V. Hayez, V. Costa, J. Guillaume, H. Terryn, A. Hubin, Micro Raman spectroscopy used for the study of corrosion products on copper alloys: Study of the chemical composition of artificial patinas used for restoration purposes, Analyst, 130 (2005), 550–556, doi:10.1039/B419080G
7. A. H. Zittlau, Q. Shi, J. Boerio-Goates, B. F. Woodfield, J. Majzlan, Thermodynamics of the basic copper sulfates antlerite, posnjakite, and brochantite, Chemie der Erde - Geochemistry, 73 (2013), 39–50, doi:10.1016/J.CHEMER.2012.12.002
8. P. Letardi, Testing new coatings for outdoor bronze monuments: A methodological overview, Coatings, 11 (2021), 1–16, doi:10.3390/COATINGS11020131
9. G. Bierwagen, T. J. Shedlosky, K. Stanek, Developing and testing a new generation of protective coatings for outdoor bronze sculpture, Prog. Org. Coatings, 48 (2003), 289–296, doi:10.1016/J.PORGCOAT.2003.07.004
10. J. Wolfe, R. Grayburn, H. Khanjian, A. Heginbotham, A. Phenix, Deconstructing Incralac: A formulation study of acrylic coatings for the protection of outdoor bronze sculpture, ICOM-CC 18th Triennial Conference, Copenhagen 2017, 1–9
11. C. J. McNamara, M. Breuker, M. Helms, T. D. Perry, R. Mitchell, Biodeterioration of Incralac used for the protection of bronze monuments, J. Cult. Herit., 5 (2004), 361–364, doi:10.1016/J.CULHER.2004.06.002
12. D. A. Scott, Copper and Bronze in Art: Corrosion, Colorants, Conservation, Getty Publications, LA, California 2002
13. M. Mihelčič, M. Gaberšček, M. Salzano de Luna, M. Lavorgna, C. Giuliani, G. Di Carlo, A. K. Surca, Effect of silsesquioxane addition on the protective performance of fluoropolymer coatings for bronze surfaces, Mater. Des., 178 (2019), 1–13, doi:10.1016/J.MATDES.2019.107860
14. T. Kosec, L. Škrlep, E. Švara Fabjan, A. Sever Škapin, G. Masi, E. Bernardi, C. Chiavari, C. Josse, J. Esvan, L. Robbiola, Development of multi-component fluoropolymer based coating on simulated outdoor patina on quaternary bronze, Prog. Org. Coatings, 131 (2019), 27–35, doi:10.1016/J.PORGCOAT.2019.01.040
15. T. Kosec, Ž. Novak, E. Š. Fabjan, L. Škrlep, A. Sever Škapin, P. Ropret, Corrosion protection of brown and green patinated bronze, Prog. Org. Coatings, 161 (2021), 1–9, doi:10.1016/J.PORGCOAT.2021.106510
16. J. Wang, Y. Wu, S. Zhang, A new coating system modified with nano-sized particles for archaeological bronze protection, Stud. Conserv., 59 (2014), 268–275, doi:10.1179/2047058414Y.0000000135
17. P. A. Schweitzer, Fundamentals of Metallic Corrosion: Atmospheric and Media Corrosion of Metals, 2nd ed., CRC Press/Taylor & Francis Group, Boca Raton 2007
18. M. Del Mar Pérez, A. Saleh, A. Yebra, R. Pulgar, Study of the variation between CIELAB ΔE* and CIEDE2000 color-differences of resin composites, Dent. Mater. J., 26 (2007), 21–28, doi:10.4012/DMJ.26.21
19. K. Marušić, H. Otmačić-Ćurković, Š. Horvat-Kurbegović, H. Takenouti, E. Stupnišek-Lisac, Comparative studies of chemical and electrochemical preparation of artificial bronze patinas and their protection by corrosion inhibitor, Electrochim. Acta, 54 (2009), 7106–7113, doi:10.1016/J.ELECTACTA.2009.07.014
20. G. Niaura, Surface-enhanced Raman spectroscopic observation of two kinds of adsorbed OH− ions at copper electrode, Electrochim. Acta, 45 (2000), 3507–3519, doi:10.1016/S0013-4686(00)00434-5
21. P. Ropret, T. Kosec, Raman investigation of artificial patinas on recent bronze – Part I: climatic chamber exposure, J. Raman Spectrosc., 43 (2012), 1578–1586, doi:10.1002/JRS.4068
22. V. Hayez, J. Guillaume, A. Hubin, H. Terryn, Micro-Raman spectroscopy for the study of corrosion products on copper alloys: setting up of a reference database and studying works of art, J. Raman Spectrosc., 35 (2004), 732–738, doi:10.1002/JRS.1194
Published
2022-12-08
How to Cite
1.
Novak Živa, Kosec T. CORROSION AND PROTECTION OF NON-PATINATED, SULPHIDE- AND CHLORIDE-PATINATED BRONZE. MatTech [Internet]. 2022Dec.8 [cited 2025Dec.15];56(6):697–704. Available from: https://mater-tehnol.si/index.php/MatTech/article/view/641
Section
Articles
