Analizy składu chemicznego oraz badania metalograficzne wybranych zabytków żelaznych z cmentarzyska w Świbiu / Chemical composition analysis and metallographic analysis of selected iron artefacts from Świbie
by Mateusz Biborski 1, Janusz Stępiński 2
1 – Uniwersytet Jagielloński, Instytut Archeologii, ul. Gołębia 11, 31-007 Kraków; 2 – AGH – Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie, professor emeritus
In: Michnik, M., Dzięgielewski, K. (2022). Cmentarzysko z wczesnej epoki żelaza w Świbiu na Górnym Śląsku. Tom 2, pp. 338-349. Gliwice: Muzeum w Gliwicach, Wydawnictwo Profil-Archeo.
Fifteen iron objects from the cemetery in Świbie, site no. 16, Gliwice District, was chosen for raw material analysis. The collection comprises of bracelets, necklaces, ankle rings, socketed axes, a flat hatchet (Ärmchenbeil), and a chisel.
The main purpose of the analyses was to identify the raw material from which the artefacts were made. All of them were subjected to non-destructive analysis of the chemical composition in the energy dispersive Spectro-MIDEX XRF spectrometer with a high count rate and high resolution. In addition, in order to detect a wider spectrum of elements, the analyses were carried out in a helium atmosphere, which allowed for more accurate measurements than with the classic XRF method (e.g. indicating the presence of potassium and other light elements). Two ankle rings from were subjected to invasive metallographic research. The artefacts selected were similar to allow for a comparative analysis. One sample covering the entire cross-section was taken from each ring. The aim was primarily to determine the technology and type of material used in their manufacture.
The research demonstrated that some of the iron artefacts from Świbie, revealing higher phosphorous content (over 0.2%), may originate from bog ores. None of them had increased Ni content to suggest meteoritic origin of the raw material. With respect to the two ankle rings subjected to more detailed analysis, the phosphorous content was confirmed by hardness (HV10) tests. The microstructure of the metal, with abundant slag inclusions, was typical of bloomery iron. Carburization of the surface of both rings was incidental rather that an intentional treatment aimed at hardening the surface. In terms of raw material processing and smithery level, the samples from Świbie are comparable to other iron samples known from Polish sites from that period.