Ancient and historic steel in Japan, India and Europe, a non-invasive comparative study using thermal neutron diffraction

Abstract

The production and refinement of steel has followed very different paths in different parts of the Eurasian continent. In aiming to characterize the similarities and differences between various smelting and smithing methods, we have analysed steel samples from four different areas and historic periods: the Kotō Age in Japan (twelfth-sixteenth century), the Moghul Empire in India (seventeenth-nineteenth century), the Ottoman Turkish Empire (seventeenth century) and the late Middle Ages (fifteenth century) in Italy. The best quality steel was employed for forging arms and armour of high quality, so that we have selected samples from Japan, India, the Middle East and Italy belonging to such a category. Traditional methods, such as metallography, used to characterize different steels in terms of their carbon contents, microconstituents and slag inclusions, entailed an invasive approach. Since many of the selected artefacts are in a very good state of conservation, a different and non-invasive approach was desirable. To this aim, we have used time of flight neutron diffraction on the Italian Neutron Experimental Station diffractometer, located at the pulsed neutron source ISIS in the United Kingdom. By this technique, we were able to quantify the phase distribution of the metal phases, the slag inclusion content, and the oxidation state of the samples, both as average concentration on the whole artefact and in selected gauge volumes. The results of the present investigation offer an interesting picture of the steel metallurgy in different areas of the world.

Characterization of an Indian sword: classic and noninvasive methods of investigation in comparison

“…They have proved to be among the most Fig. 1 The Shamsheer mounted on a rigid frame effective methods for the noninvasive characterization of precious specimens of archaeometallurgical interest [7][8][9][10]. These techniques can provide useful microstructural properties of the constituent materials as well as a quantitative phase analysis of the investigated volume.…”

“…The analysis of the diffraction profile performed using one perturbative expansion in spherical harmonics is able to provide an index of the texture (J) which is a function of the level of orientation of the domains. The size of the domains is calculated using the Scherrer's law D = K S *DT/c 2 ; where c 2 is the Lorentian secondary broadening, K S is the Scherrer's constant and is 0.8 in the case of neutron diffractometers in ToF and DT is the conversion constant from ToF to its d-spacing of a specific detector on which measurement is made [8,9,11,15,16]. This relationship has an upper limit of validity which, in the case of the diffractometer INES, is equal to 200 nm.…”

Modern and Historical Engineering Components Investigated by Neutron Diffraction on ENGIN-X

“…The ENGIN-X beamline has successfully been used to investigate strain, phase composition in various structures of historical [30][31][32]36] and archaeological [33][34][35] samples.…”

“…The study focused on two Japanese long swords in order to determine the composition of the steel, the presence of phases related to the smelting (fayalite, wuestite, troilite) and the presence of oxides due to the mineralization (goethite, magnetite, hematite) [37][38]. The two swords investigated, pertain to two different traditions of the Koto Age: the Bizen (Kanesada school) and the Mino (Aoe school) of the Koto (Ancient sword) age [30][31]. The former developed as one of the two most ancient and was born in the southern part of Honshu Island while the latter developed in the Mino province.…”

Simultaneous and integrated neutron-based techniques for material analysis of a metallic ancient flute

“…Neutron diffraction (ND) [1,2] results determine the phase composition and microstructural properties of materials, neutron resonance capture analysis (NRCA) [3,4] provides the elemental composition and neutron radiography (NR) 7 Author to whom any correspondence should be addressed. 8 Present address: ENEA-Cenro Ricerche Frascati, Via E Fermi 45, 00044 Frascati, Rome, Italy. and neutron tomography (NT) [5,6] recognize internal features of the samples.…”