Application of µ-Raman spectroscopy to the study of the corrosion products of archaeological coins

Authors

  • Tilde de Caro National Research Council (ISMN-CNR), Rome, Italy
  • Emma Angelini Politecnico di Torino, Torino, Italy
  • Leila Es Sebar Politecnico di Torino, Torino, Italy

DOI:

https://doi.org/10.21014/acta_imeko.v10i1.893

Abstract

In this paper, a study of the corrosion products formed on archaeological bronze artefacts excavated in Tharros (Sardinia, Italy) is presented. The investigation was carried out by means of the combination of different analytical techniques, including optical microscopy, micro-Raman spectroscopy (µ-RS), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and X-ray diffraction. The artefacts under study are three bronze coins from the Phoenician–Punic period that are deeply corroded due to the chloride-rich soil of the Tharros excavation site. µ-Raman spectroscopy was chosen to investigate the corroded surfaces of the artefacts because it is a non-destructive technique, it has high spatial resolution, and it makes it possible to discriminate between polymorphs and correlate colour and chemical composition. Through µ-RS, it was possible to identify different mineralogical phases and different polymorphs, such as cuprite (Cu2O), copper trihydroxychloride [Cu2Cl(OH)3] polymorphs, hydroxy lead chloride laurionite [PbCl(OH)] and calcium carbonate polymorph aragonite. The experimental findings highlight that micro-Raman spectroscopy can be used to provide further knowledge regarding the environmental factors that may cause the degradation of archaeological bronzes in soil.

Author Biographies

Tilde de Caro, National Research Council (ISMN-CNR), Rome, Italy

Istituto per lo Studio dei Materiali Nanostrutturati (ISMN)

Emma Angelini, Politecnico di Torino, Torino, Italy

Dipartimento di Scienza Applicata E Tecnologia (DISAT)

Leila Es Sebar, Politecnico di Torino, Torino, Italy

Dipartimento di Scienza Applicata E Tecnologia (DISAT)

Downloads

Additional Files

Published

2021-03-31

Issue

Vol. 10 No. 1 (2021)

Section

Research Papers

License

Authors who publish with this journal agree to the following terms:

  • Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
  • Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
  • Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).