First examinations of ancient ferrous alloys in Renaissance armour by SR-X-Ray diffraction

International audience; The paper aims at understanding the nature of ferrous alloys used for the fabrication of Renaissance armour in a Nuremberg workshop, owned by Valentin Siebenbürger. Noninvasive techniques such as X-Ray Diffraction (XRD) using synchrotron radiation (SR) are well suited to identify the different crystalline phases, characteristic of ancient ferrous alloys, avoiding multiple sampling, rarely allowed in the case of museum pieces. However, such experiment presented analytical challenge due to the complex shape of armours. Our goal was to demonstrate the feasibility of SR-XRD measurement to identify mineral phases contained in ferrous alloys (cementite, ferrite, martensite…) on large and complete museum amour pieces and provide new insights on Renaissance armour manufacturing. The study allowed identifying phases characteristic of ancient ferrous alloys (ferrite, cementite …) but also the presence of heat treatment, on some armour plates, giving new information on manufacturing technique and workshop organization.