Development of an Optimized NDT Methodology for the Investigation of Ancient Greek Copper-Based Artifacts

Amani-Christiana Saint,Vasiliki Dritsa,Maria Koui

doi:10.3390/cmd2020017

Amani-Christiana Saint, Vasiliki Dritsa + Show 1 more

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https://doi.org/10.3390/cmd2020017

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Abstract

A multi-analytical non-destructive testing (NDT) methodology was applied to copper-based artifacts originated from various archaeological sites of Greece. X-ray fluorescence (XRF), fiber optics diffuse reflectance spectroscopy (FORS) and scanning electron microscopy coupled with an energy dispersive X-ray detector (ESEM-EDX) were used for the characterization of the alloys and the corrosion products. The key elements of the artifacts belonging to the Early Bronze Age (2700–2300 BC) were copper and arsenic, while tin bronze was used for the fabrication of the Late Bronze Age (1600–1100 BC) artifacts. The effectiveness of XRF for the determination of the bulk composition was confirmed by comparative study with the previously applied atomic absorption spectroscopy (AAS) and inductively coupled plasma–atomic emission spectrometry (ICP-AES) destructive techniques. Significant differences between the artifacts were revealed through the spectral measurement of their surface corrosion products color by FORS. ESEM-EDX provided information on the microstructure, the elemental composition of the corrosion layers and bulk, as well as the distribution of the corrosion products on the surface. Conclusively, the combined NDT methodology could be regarded as a valuable and appropriate tool for the elemental composition of the bulk alloy, thus leading to the classification of their historical period and the corrosion products, contributing significantly to their conservation–restoration.

Highlights

X-ray fluorescence (XRF) analysis was applied on the surface of the copper-based artifacts in order to yield qualitative and quantitative information regarding the chemical elemental composition, enabling the characterization of the metal or metal alloy, the identification of the historical period of copper-based artifacts through evidence of key-elements, having the potential to relate metal compositions to ore deposits through their minor element pattern
Tin bronze alloys prevailed in Late Bronze Age, as copper and tin were the main elements in the selected copper-based objects
XRF technique is performed on the surface, it is well-suited for the identification of the alloys, as the results are in good agreement with the elemental concentration values of previously applied atomic absorption spectroscopy (AAS) and inductively coupled plasma–atomic emission spectrometry (ICP-AES) techniques

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Copper was the first metal used and dates back at least ten thousand years B.C. The first evidence for the exploitation of copper ore comes from the region of Anatolia and. Iran, where copper objects date from the 9th to the 7th millennium B.C. During the 4th millennium B.C., the practice of alloying became widely known and used during the Early

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