Recovering bronze metallurgy from archaeological artefacts for the production of reference materials in conservation science

The production of reference Cu-based alloys is the first step of an original experimental protocol to be used in the field of conservation and restoration of metal artefacts. The production of these synthetic alloys has a double value. They can be used both as suitable substitutes of unique archaeological pieces for testing new materials and methods for conservation, and as guidelines for contemporary metal production. We report on a research activity focused on the recovery of the ancient production techniques from the investigation of archaeological copper-based artefacts. The chemical, physical and metallurgical characterization of several Cu-based artefacts, found in different Italian archaological sites, was carried out by bulk and surface techniques in order to investigate the nature and properties of the metallic substrates and the corrosion products. Chemical and metallurgial formulations of the ancient archaeological alloys were obtained by data analyses. On the basis of these results, a set of Cu-based alloys with different chemical compositions and metallurgical features was produced. The chemical and physical characterization showed that these modern Cu-based alloys strictly resemble the ancient ones constituting the archaeological artefacts from a chemical, micro-morphological and metallurgical point of view.