Neutron tomography of a corroded Han dynasty <i>shu dao</i> (书刀) using the Energy-Resolved Neutron Imaging Instrument

Iron-based cultural artefacts from ancient China are severely threatened by corrosion, and traditional non-destructive imaging techniques ( e.g. X-ray imaging) face shortcomings in analysing the composite structures of metals, corrosion products and organic materials: low-energy X-rays cause metal hardening artefacts, while high-energy X-rays are minimally attenuated by organic components, leading to incomplete structural characterization. To address this scientific challenge, this study employed neutron tomography using the Energy-Resolved Neutron Imaging Instrument at the China Spallation Neutron Source to conduct non-destructive characterization of a corroded Han dynasty shu dao , a typical iron-based knife used for editing bamboo slips in ancient China. Neutrons exhibit unique advantages: strong penetration of iron matrices and high sensitivity to hydrogen, enabling clear differentiation between corrosion products and the intact iron matrix. The results demonstrate that neutron tomography enables the detection of rusted regions on the knife to characterize corrosion severity, segmentation of the blade's crack network, observation of the scabbard's layered structure and measurement of key features such as the blade's reinforcement.