Electron backscattering diffraction as a complementary analytical approach to the microstructural characterization of ancient materials by electron microscopy

• SEM-EBSD characterizes local crystallography at the nanoscale.
• EBSD adds phase-identification and crystallographic parameters to chemical data.
• Only EBSD provides the necessary crystallographic information in a wide enough area.
• Single sample preparation to obtain chemical, textural and crystallographic data.

Since the development of electron backscattering diffraction (EBSD), scanning electron microscopy (SEM) has become a powerful tool for characterizing the local crystallography of bulk materials at the nanoscale. Although EBSD is now a well-established characterization method in materials science, it has rarely been used in art and archaeology, and nearly exclusively in metallic materials. However, EBSD could also be exploited to characterize ancient materials and to highlight their local crystallography (e.g., in the study of natural or artificial pigments). We discuss the potential of EBSD, as outlined in studies and from its application with an ancient material – Egyptian blue – in identification of crystalline phases, drawing phase maps, and the extraction of several microstructural parameters (e.g., the grain size and the aspect-ratio distribution of phases).