Microchemical Study of the Corrosion products on ancient Bronzes by means of Glow Discharge Optical Emission Spectrometry

Glow discharge optical emission spectrometry (GDOES) has been used for studying the corrosion product layers, i.e. the patinae, on Punic bronze artefacts found at Tharros (western Sardinia, Italy) during an archaeological excavation. For all these materials, the results show that via GDOES it is possible to obtain reliable and reproducible quantitative chemical composition for the bulk alloys by taking into account that bronze artefacts are quite inhomogeneous. Some examples of the GDOES analytical capability as elemental depth–concentration profiles through thick bronze patinae are shown and briefly discussed in combination with the microchemical features obtained via scanning electron microscopy/energy dispersive spectrometry (SEM+EDS) and x-ray diffraction (XRD). These results show that GDOES, with its ability for routine and rapid analysis of layers of thickness up to 120 µm, has significant potential in studies of the corrosion products and for the restoration and conservation of ancient bronzes.