Microstructure of natural plywood-like ceramics: a study by high-resolution electron microscopy and energy-variable X-ray diffraction

Abstract

The three-dimensional microstructure of a Strombus decorus persicus seashell was studied by means of high-resolution electron microscopy and energy-variable X-ray diffraction on synchrotron beam lines. Energy variation in small steps allows the X-ray penetration depth to be changed precisely and, on this basis, for a non-destructive microstructural analysis with depth resolution to be developed. This technique enabled determination of depth-resolved microstructural parameters, such as the degree of the preferred orientation, the lamella size, and average microstrain fluctuations in both the prismatic and the crossed-lamellar layers of these seashells. The X-ray results were in good agreement with direct observations made by electron microscopy. A detailed study of the shell microstructure shed additional light on the relationship between the structural characteristics and superior mechanical properties of seashells.