Early Iron Age ferrous artefacts from southeastern Arabia: investigating fabrication techniques using neutron tomography, optical microscopy, and SEM-EDS

Abstract

The study presents a new approach for the investigation of ancient ferrous artefacts, by combining non-invasive and invasive techniques: neutron tomography, optical microscopy, and SEM-EDS, as applied to the objects from Saruq al-Hadid, U.A.E. It is revealed that despite the severe degradation of the objects, neutron tomography allows the detection of various features associated with the mechanisms of degradation and working (manufacturing, re-processing) of the ferrous artefacts including (1) different corrosion products and their specific distribution patterns; (2) surface dents from the use of hammers; and (3) various structural heterogeneities such as mineralised pierced holes, incised patterns, and ex-welding lines. The ex-welding lines present in every artefact have a major significance because they can be conveniently used for the investigation of the manufacturing techniques of the objects. The complementary invasive investigation via optical microscopy (OM) and SEM-EDS is used to relate the carburization patterns of the objects to their welding techniques, which are then associated with the patterns of variability of slag inclusion composition. The integrated data provide insight into the socio-technological aspects underlying the choices in the manufacturing of the Saruq al-Hadid objects, and broader aspects of early Iron Age iron-working in the ancient Near East.