Correlative multimodal techniques combined with X-ray Microscopy for investigating ancient metallurgical practices and corrosion processes

X-ray Microscopy (XRM) has proven to be a powerful tool for studying ancient metallurgical processes, providing high-resolution 3D imaging of internal structures while integrating effectively with complementary analytical methods. This study explores the potential of XRM in combination with optical and electron microscopy and X-ray fluorescence (XRF) to enhance the multiscale and multimodal investigation of archaeological metals. This correlative approach is applied through case studies on Etruscan gold jewelry from Pyrgi (Santa Severa, Italy), as well as Phoenician-Punic bronze coins and iron nails from Motya (Sicily, Italy). For Etruscan gold jewelry from Pyrgi, the synergy between XRM and XRF was essential in examining goldsmithing techniques and the heterogeneous composition of gold-silver alloys across different decorative components. This fully non-invasive approach allowed for the identification of compositional variations without the need for sampling, offering new insights into the technological choices of Etruscan craftsmen. When applied to Phoenician-Punic bronze coins, the combination of XRM with optical and electron microscopy enabled the analysis of micro-segregation phenomena, recrystallization, and corrosion processes. Similarly, in the case of corroded iron nails from Motya, XRM provided a 3D visualization of internal fractures and stratified corrosion layers, while correlative optical and electron microscopy on cross-sections, combined with micro-Raman spectroscopy, allowed for a detailed analysis of microstructures and corrosion compounds. These case studies highlight the versatility of XRM in addressing different challenges across gold, bronze, and iron artifacts. Furthermore, advanced software solutions and artificial intelligence (AI) enhance X-ray imaging by improving reconstruction, reducing artifacts such as beam hardening in dense materials like gold, and refining imaging quality for more accurate analysis. The strategy of XRM and XRF integration, along with optical and electron microscopy for compositional and microstructural assessment, enhances our understanding of ancient metallurgical techniques and supports the development of conservation strategies for cultural heritage materials.