A Study of the Corrosion Mechanism in Some Bronze Artifacts found in the Bazman Spidej Cemetery, Southeast Iran

The ancient bronze artifacts (archaeological objects) in various forms are one of the most important artifacts that have been discovered from excavated Bronze Age sites, southeast Iran. various bronze artefacts belonging to Bazman Spidej Cemetery one of the notable archaeological sites, Sistan and Baluchestan, Iran. More of these artifacts have been deteriorated and partially destroyed due to long-term burial environment, suffer from various corrosion occurs on the surface of or inside the bronze artifacts. this research in an attempt to study type and corrosion process, as well as the study of their corrosion stratigraphy of the six discovered bronze artifacts. In this regard, these artefacts have examined to study by analytical methods such as optical microscopy (OM), scanning electron microscopy with coupled energy-dispersive spectroscopy (SEM-EDS) and also from X-Ray diffraction (XRD) measurements to examine the corrosion stratigraphy and decuprification (selective dissolution of copper) process. The results show effect of corrosion stratigraphy, the corrosion structure indicates three inner layers in two samples and two inner layers in three samples, and also the layer of outer corrosion layer was also detected in all samples in the sample types except one sample (Spd4). In the bronze artifacts, this structure is associated with the occurrence of decuprification (selective dissolution of copper) process. and the infiltration of oxygen into the metal core in linked to the formation mechanism of tin rich layer. Therefore, the results indicate the decuprification process in all samples except one sample (Spd2). The results indicate the identification of three different corrosion phases including Cuprite, atacamite and paratacamite, which indicates bronze disease in the existing samples and also The structure of corrosion occurred in the study samples study Is related to. corrosion II type in bronze artifacts.