Tracing manufacturing technique in an archaeological thin sheet tube from tepe sagzabad in Qazvin plain, Iran (1500-800 BC)
Part of : Mediterranean archaeology & archaeometry : international journal ; Vol.15, No.1, 2015, pages 1-10
Issue:
Pages:
1-10
Abstract:
Recent excavations in Tepe Sagzabad in Qazvin Plain, Iran, yielded some archaeological metal artifacts dating to the Early Iron Age. Among different metal fragments, a small tube was found. As a part of systematic analytical research, thin sheet tube was studied for elemental composition, manufacturing technique and deterioration mechanism using optical microscopy (OM), scanning electron microscopy combined with energy dispersive X-ray spectroscopy (SEM-EDS) and Raman spectroscopy. The results of analyses showed that the tube has been made from a thin sheet Cu-Sn alloy. In addition, it was found that the tube was completely mineralized, and there was no sound metal remained in it. Corrosion of the tube was composed of a bilayer structure in which the original shape of the artifact has been preserved. Raman characterization of the corrosion products showed that the inner layer is composed mainly of cupric oxide (tenorite) beneath an outer cuprous oxide layer (cuprite) which has grown outward from the original surface. This is believed to be due to a corrosion phenomenon of bronze alloys known as "decuprification process". Moreover, microscopic investigation showed presence of elongated inclusions merely in the inner layer indicating both the manufacturing process and the limit of the original surface of the tube.
Subject:
Subject (LC):
Keywords:
archaeological bronze, sheet tube, SEM-EDS, Sagzabad, Raman spectroscopy
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