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Corrosion investigation of fire-gilded bronze involving high surface resolution spectroscopic imaging

Masi, Giulia and Chiavari, Cristina and Avila, José and Esvan, Jérôme and Raffo, Simona and Bignozzi, Maria Chiara and Asensio, Maria C. and Robbiola, Luc and Martini, Clara Corrosion investigation of fire-gilded bronze involving high surface resolution spectroscopic imaging. (2016) Applied Surface Science, 366. 317-327. ISSN 0169-4332

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Official URL: http://dx.doi.org/10.1016/j.apsusc.2016.01.101

Abstract

Gilded bronzes are often affected by severe corrosion, due to defects in the Au layer and Au/Cu alloygalvanic coupling, stimulated by large cathodic area of the gilded layer. Galvanic corrosion, triggered bygilding defects, leads to products growth at the Au/bronze interface, inducing blistering or break-up ofthe Au layer. In this context, fire-gilded bronze replicas prepared by ancient methods (use of spreadableAu–Hg paste) was specifically characterised by compiling complementary spectroscopic and imaginginformation before/after accelerated ageing with synthetic rain. Fire-gilded bronze samples were chem-ically imaged in cross-section at nano-metric scale (<200 nm) using high energy and lateral resolutionsynchrotron radiation photoemission (HR-SRPES) of core levels and valence band after conventionalcharacterisation of the samples by Glow Discharge optical Emission Spectroscopy (GD-OES) and conven-tional X-ray photoelectron spectroscopy (XPS). We have found a net surface enrichment in Zn and Snafter fire-gilding and presence of metallic Hg, Pb and Cu within the Au layer. Moreover, the compositiondistribution of the elements together with their oxidation has been determined. It was also revealed thatmetallic phases including Hg and Pb remain in the gilding after corrosion. Moreover, selective dissolu-tion of Zn and Cu occurs in the crater due to galvanic coupling, which locally induces relative Sn speciesenrichment (decuprification). The feasibility advantages and disadvantages of chemical imaging usingHR-SRPES to study artworks have been investigated on representative replicas.

Item Type:Article
Additional Information:Thanks to Elsevier editor. The definitive version is available at http://www.sciencedirect.com The original PDF of the article can be found at http://www.sciencedirect.com/science/article/pii/S0169433216001380
HAL Id:hal-01494641
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Commissariat à l'Energie Atomique et aux énergies alternatives - CEA (FRANCE)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Other partners > Università di Bologna (ITALY)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Université de Toulouse > Université Toulouse - Jean Jaurès - UT2J (FRANCE)
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Deposited By: cirimat webmestre
Deposited On:23 Mar 2017 16:25

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