Micro-chemical and micro-structural investigation of the corrosion products on “The Dancing Satyr” (Mazara del Vallo, Sicily, Italy) (original) (raw)
Integrated analytical methodologies for the study of corrosion processes in archaeological bronzes
… Acta Part B: Atomic …, 2011
The investigations on structure and micro-chemical composition of archaeological metal alloys are needed in archaeometry. The aim of this study is devoted both to acquire information about their provenance and production technology, and to improve our understanding about the corrosion processes. In this paper we present the study of the corrosion phenomena of bronze samples, laboratory-made according to binary, ternary and quaternary alloys typical of Roman archaeometallurgical production through an integrated methodology based on the use of non or micro invasive physical techniques. Among the analysed samples, two were artificially aged through burial in the archaeological site of Tharros, along the west coast of Sardinia (Italy). The corrosion products, typical of the bronzes in archaeological sites near the sea, have been characterized by non invasive and micro-destructive measurements. In particular, the corrosion patinas were examined through optical microscopy, scanning electron microscopy and microanalysis, X-ray fluorescence and laser ablation spectroscopy. The use of integrated technologies allowed us to determine both the elemental composition and surface morphology of the patina, highlighting the correlation between patina nature and chemical composition of the burial context. Moreover, data obtained by the laser-induced breakdown spectroscopy along the depth profile on the samples, have yielded information about the stratigraphic layers of corrosion products and their growth. Finally, the depth profiles allowed us to verify both the chemical elements constituting the patina, the metal ions constituting the alloy and the occurrence of migration phenomena from bulk to the surface.
X Study on the Specific Effects of Corrosion Processes on Ancient Bronze Artefacts
The paper presents the cases of the corrosion processes which take place on starting from the usage period when the primary patina is being formed and when the secondary patina starts, than continuing with the archaeological site where the contamination patina is obtained under the influence of the pedological processes. The paper is a review from the specialised literature and from the contributions of the authors. There has been used the direct analysis with optical instruments, electron microscopy and EDX.
A long-term corrosion investigation of bronze sculptures exposed outdoor
2019
Safeguarding our cultural heritage for the future generations is possible only by applying tailored conservation strategies. The safeguard is a complex task and often requires measurements to be performed on the artefacts. This paper describes an interesting case regarding the metallic artefacts belonging to the Gori Art Collection at Fattoria Celle (Pistoia, Italy). This collection of modern art, developed inside a project of environmental art, is facing different corrosion phenomena due to its permanent exposure to outdoor environmental conditions. A non-invasive and in-situ multi-analytical approach was recently started in order to assess the conservation state of the metal artefacts and to assure their long-lasting preservation trough the development of a conservation project. In this paper, the preliminary results of the monitoring campaign carried on the bronze sculpture "Cavaliere" by Marino Marini will be presented and discussed.
In-situ multi-analytical study of ongoing corrosion processes on bronze artworks exposed outdoor
ACTA IMEKO
This paper presents a long-term in-situ campaign to monitor contemporary bronze statuary exposed outdoors. The case study relates to the characterisation of three sculptures belonging to the Gori Art Collection, located in the Fattoria di Celle: ‘Cavaliere’ and ‘Miracolo – Composizione’ by Marino Marini and ‘Due forme o due ombre n°2’ by Luciano Minguzzi. The overall conservation state of the sculptures was investigated by means of a multi-analytical and non-invasive approach, involving different techniques. Three-dimensional photogrammetry was performed to fully document the artworks. The chemical and microstructural features of the corrosion patinas were then characterised through X-ray fluorescence and Raman spectroscopy. In addition, the stability and the protective effectiveness of the corrosion products were assessed by electrochemical impedance spectroscopy. Thanks to the combined use of these specific techniques, the information extracted through the different analyses could...
2010-Morphology of Corrosion on Excavated Archaeological Metal Artefacts
The present paper is studying the nature and stromatography of corrosion products formed on metal artefacts found on archaeological excavations in the prefecture of Ioannina. Copper and iron alloy artefacts were examined by different analytical techniques (Optical Microscopy, SEM-EDS, XRD). The alloys were identified as 10% bronze and wrought iron, respectively. Soil samples from the excavation areas were analyzed in order to correlate the soil elements with the corrosion products formed on both alloys. Two types of soil were identified: a sandy-clay soil and a calcareous one with variable pH and up to 90ppm chloride ions. A similar corrosion pattern is observed in both types of alloys. Despite their heavy corrosion in most cases, the metal core is preserved, followed by layers of oxides and hydroxides. Towards the artifact's surface, the corrosion products are gradually enriched with chemical elements from the burial soil.
A Review of the Corrosion Behavior of Metallic Heritage Structures and Artifacts
Jurnal Teknologi, 2015
Awareness about restoring and preserving historically important structures and artifacts is gradually growing in many parts of the world. These artifacts and structures represent the culture, tradition and past of a nation. They are often also a source of national income through tourist activities. Besides masonry and wood work, metallic forms and relics are a vital part of the heritage which needs to be conserved. Certain metals have been used significantly throughout history in the creation of objects and structures. However, metals are prone to decay over time, particularly decay through corrosion. The basic mechanisms of metal corrosion, the various types of corrosion and existing remedial solutions are reviewed in this paper. The most significant factor affecting metal corrosion was found to be the surrounding environment, especially in marine areas. Different remedial measures can be implemented on corroded metals according to their specific properties. Recommendations for fur...
A spearhead of archaeological and cultural significance has been found and analysed in Serbia. In the corrosion products of the artefact, the dominant phases were goethite (α-FeO(OH)) and magnetite (Fe 3 O 4) whose presence explains a good preservation of the base metal, iron, over the centuries and the artefact stability after excavation. Besides goethite and magnetite, the corrosion products were identified to contain, to a lesser extent, less stable lepidocrocite (γ-FeO(OH)) and the phases that come from the rocks and soil from the surrounding environment (plagioclase). The phases containing chloride ions were not detected in the corrosion products (akaganéite, β-Fe 8 O 8 (OH) 8 Cl 1.35), which indirectly indicates that the content of chloride ions was not significant in the underground exploitation conditions. The lack of chloride ions also contributed to the corrosion stability of the artefact during the period after excavation.
Corrosion Stability of Corrosion Products on an Archaeological Iron Artefact
2012
A spearhead of archaeological and cultural significance has been found and analysed in Serbia. In the corrosion products of the artefact, the dominant phases were goethite (αFeO(OH)) and magnetite (Fe3O4) whose presence explains a good preservation of the base metal, iron, over the centuries and the artefact stability after excavation. Besides goethite and magnetite, the corrosion products were identified to contain, to a lesser extent, less stable lepidocrocite (γ-FeO(OH)) and the phases that come from the rocks and soil from the surrounding environment (plagioclase). The phases containing chloride ions were not detected in the corrosion products (akaganéite, β-Fe8O8(OH)8Cl1.35), which indirectly indicates that the content of chloride ions was not significant in the underground exploitation conditions. The lack of chloride ions also contributed to the corrosion stability of the artefact during the period after excavation.