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The characterization of Sn‐based corrosion products in ancient bronzes: a Raman approach
Author(s) -
Ospitali Francesca,
Chiavari Cristina,
Martini Carla,
Bernardi Elena,
Passarini Fabrizio,
Robbiola Luc
Publication year - 2012
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4037
Subject(s) - corrosion , characterization (materials science) , bronze , tin , raman spectroscopy , materials science , metallurgy , scanning electron microscope , chemistry , nanotechnology , composite material , physics , optics
The characterization of corrosion patinas on bronzes is preliminarily connected to the determination of proper conservation strategies. Moreover, it also provides an essential contribution to the comprehension of the mechanisms of formation of patinas. Concerning the last aspect, several studies highlighted that bronze corrosion behaviour cannot be assimilated to that of pure copper. In particular, decuprification and relative enrichment of tin in the corrosion layers were observed. Tin therefore, together with its insoluble salts, plays an important role in the mechanism of formation of bronze patinas. Thus, the characterization of Sn‐based corrosion products becomes fundamental, although remaining quite problematic. This work reports several case studies where Sn‐based corrosion products grown in bronzes have been identified, thanks to the hyphenated system scanning electron microscopy–energy dispersive spectrometry–Raman structural and chemical analyser. Combining the main characteristics of these techniques, different Sn‐containing compounds, mainly crystalline and nano‐sized tin dioxides, were detected in bronze patinas exposed to different environments (to the atmosphere, in both natural and accelerated ageing conditions, and to the soil). The main issues regarding the interpretation of Raman spectra of these compounds are presented and discussed. Copyright © 2012 John Wiley & Sons, Ltd.