Patina Formation and Corrosion Processes in Sefidruy Beta Bronze Artifacts From the Rasht Archaeology Museum, Iran

High‐tin bronze artifacts, known as Sefidruy vessels and preserved in the Rasht Archaeology Museum, Iran, were examined to investigate patina formation and corrosion processes. Dating mainly to the Sasanian period (224–651  ce ) and originating from Gilan province, these objects reflect a distinct copper–tin alloying tradition. Elemental analyses confirmed 20wt%–22 wt% tin with minor lead, whereas metallography revealed α and β (martensitic) phases characteristic of β bronze. X‐ray diffraction identified cuprite, malachite, and cassiterite, formed through selective phase corrosion. Results demonstrate the relationship between alloy composition, microstructure, and patina development, offering insights into technological practices and artifact preservation.