Characteristics of corrosion products on Han iron artifacts from riverside cemeteries in Wanzhou, Chongqing, China

Abstract The study investigated the corrosion products on four Han Dynasty (206 BC–220 AD) iron artifacts excavated from riverside cemeteries in the Three Gorges Reservoir Area of Chongqing, China using Raman spectroscopy, SEM-EDS, and digital microscopy. Three artifacts from Wanzhou (near the Yangtze River) were analyzed to characterize their corrosion structures. Another iron sword from Wushan (located near the Daning River, a tributary of the Yangtze River) was selected for comparison to study the differences in the composition and distribution of corrosion products resulting from different burial environments. Results showed that goethite (α-FeOOH), lepidocrocite (γ-FeOOH), and magnetite (Fe₃O₄) were found in all samples, while akaganeite (β-FeOOH) was present only in the Wushan artifact. Lepidocrocite with red spherical shells existed at the magnetite-goethite interface in all samples. These findings highlighted the influence of local environmental factors on the corrosion products of iron artifacts excavated from the Chongqing Three Gorges Reservoir Area.