Material Studies on Decorative Buttons from the Hallstatt Period Tumuli in Mitterkirchen, Marchland, Upper Austria

Abstract

The burial ground at Mitterkirchen belongs to the Early Iron Age, respectively, to the Hallstatt culture. A remarkable find from Mitterkirchen is approximately 3,000 buttons that were attached to a magnificent coat. Five of these buttons were provided for nondestructive material examinations using computed tomography (CT). Two of these buttons could be examined by metallography, light optical microscope (LOM), scanning electron microscope (SEM) with energy-dispersive X-ray analysis (EDX) and X-ray fluorescence examination (XRF). Based on the results of the investigation, it can be assumed that the bronze buttons were manufactured by a casting process. The bronze alloys are very different, which suggests the use of various starting materials including recycled copper alloys. The microstructure of the bronzes is uniform and, depending on their compositions, contains precipitates like Pb and the intermetallic phase Cu₄₁Sn₁₁. The corrosion layers exhibit a pronounced Sn enrichment and contain malachite.