Metallographic approach to the investigation of metallic archaeological objects

Metallic objects are considered among the most significant findings in Cultural Heritage and represent the 'culture of Materials' and the habits of an historical period and of a population. They also preserve traces of time: from the transformation of the ores in metal (by smelting) to the degradation from metal to oxidised compounds (by corrosion processes). Metallography, historically devoted to connect the microstructural features to production processes and to chemical-physical-mechanical properties is a powerful and relatively easy approach to characterise metallic findings. All analytical tools and methods in the hands of a metallographer are improved through experience and practice and provide a large number of information (elemental composition, primary and secondary microstructures, surface treatments, corrosion rate, original ores traces) by the preparation of a fairly small microdestructive sample. A wise and careful use of the metallography allows the balance "object sacrifice/knowledge improvement" to lean on the right side contributing to the hard work of rebuilding humankind history. Beside a description of a research protocol some practical examples concerning archaeological findings are presented in this paper.