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Micro‐Raman spectroscopy (μ‐RS) has been used to characterize mineralogical phases of corroded iron materials, buried in lagoon‐like and calcarenitic hypogea environments. A set of samples from the Phoenician site of Motya (8th–6th centuries BC, Sicily) and from the Punic Necropolis of Lilybaeum (4th century BC, Sicily) were analyzed combining μ‐RS with scanning electron microscopy‐energy‐dispersive X‐ray spectroscopy (SEM‐EDS) and high‐resolution field emission scanning electron microscopy (HR‐FESEM). Micro‐Raman results revealed the presence of magnetite, goethite, lepidocrocite, and hematite as the main corrosion products and soil minerals as quartz, calcite, barite, actinolite, microcline, zircon, and Ti‐oxides. SEM and HR‐FESEM allowed exploring micro‐ and sub‐micrometer structures of iron oxy‐hydroxides though sections from rim to core. The different corrosion models suggest polymorphic inter‐conversions among iron oxy‐hydroxides and dissolution‐re‐precipitation reactions. In addition, the occurrence of magnetite and metal core that survived in armors buried in the hypogea site of Lilybaeum indicates more stable environmental conditions than those of Motya.

This work is the first archaeometric investigation on copper and iron wastes from the Phoenician site of Motya (Sicily, Italy), dating back to the 8 th to the 4 th century BC. The samples were analyzed through micro-Raman Spectroscopy (μ-RS), Optical Microscopy (OM), Scanning Electron Microscope-Energy-Dispersive X-ray Spectroscopy (SEM-EDS), High-Resolution Field Emission Scanning Electron Microscopy (HR-FESEM), and Electron Micro-Probe Analysis (EMPA). Micro-Raman techinique permitted to identify both primary phases, for example, calchopyrite, and secondary products such as cuprite and copper thrihydroxychlorides in the Cu-slags and goethite in the Fe-slags. SEM and HR-FESEM imaging showed the occurrence of inhomogeneous microstructures in the Cu-and Fe-slags due to elements segregation, solidification, and corrosion. EMPA data revealed that the archaeometallurgical wastes from Motya can be differentiated on the basis of their chemical compositions. These preliminary results showed different typologies of byproducts, such as base metals speiss, copper slags from smelting sulfide ore with matte, and iron smelting and smithing slags, suggesting different stages of copper and iron productions.

The best strategy to tackle complexity when analyzing corrosion in iron artefacts is to combine different analytical methods. Traditional techniques provide effective means to identify the chemistry and mineralogy of corrosion products. Nevertheless, a further step is necessary to upgrade the understanding of the corrosion evolution in three dimensions. In this regard, Multiscale X-ray Microscopy (XRM) enables multi-length scale visualization of the whole object and provides the spatial distribution of corrosion phases. Herein, we propose an integrated workflow to explore corrosion mechanisms in an iron-nail from Motya (Italy) through destructive and non-destructive techniques, which permit the extraction of the maximum information with the minimum sampling. The results reveal the internal structure of the artefact and the structural discontinuities which lead the corrosion, highlighting the compositional differences between the tip and the head of the iron nail.