3D fractures analysis and conservation assessment of wrought iron javelin through advanced non-invasive techniques.

3D imaging is a powerful tool of high resolution and non-destructive imaging technology for the study of ancient weapons and military technology, which reveals the original microstructures and corrosion patterns that threaten these artefacts. Here we report quantitative analysis of the 3D distribution and the orientation of fractures, and uncorroded metal particles within a wrought iron javelin unearthed at the Phoenician-Punic site of Motya, Italy. The study aimed to gain a better understanding of the relationship between corrosion and local stresses within the artifact and to evaluate its manufacturing technology, as well as the effects of post-treatment with Paraloid B72 on concretion and mineralized layers. The cracks were quantified in terms of content, size, and orientation. The condition of artefact storage was evaluated by a multi-analytical approach, including X-ray microscopy, field emission electron microscopy and micro-Raman spectroscopy. The results indicated that a specific technique was used to create a sturdy, lightweight javelin with a central shaft for piercing or thrusting. The fractures appear elongated in the direction of the longitudinal axis of the blade, showing the forging direction of the original metallic block. The study concluded that the artifact had not yet been stabilized due to the presence of lepidocrocite.

A comprehensive strategy for exploring corrosion in iron-based artefacts through advanced Multiscale X-ray Microscopy.

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.