Nano-crystallization in decorative layers of Greek and Roman ceramics

Abstract

Besides metallic nanocrystals of lusterware (Chapter "Lustre and Nanostructures-Ancient Technologies Revisited"), other nanoscale crystals can be found in ancient ceramics and more specifically in their decorative layers or coatings. These crystals can play a major role in the physical properties of these thin layers or can be an indicator of the manufacturing process. These thin layers are formed during firing and result from physicochemical reactions among the diverse compounds of raw preparation. In general, the firing conditions are not suitable for obtaining large crystals and many of the formed phases have crystal sizes of a few tens nanometres. Over a long period of time and throughout the world, the variety of raw preparations and firing conditions used are so diverse that it is not conceivable to give here an exhaustive rundown. In this chapter, we will focus our attention on some decorative layers of Greek and Roman potteries for which oxide nanocrystals play a key role regarding the optical and/or mechanical properties. These decorations were obtained from clay preparations and their physical properties result directly from the nanocrystalline size and the behaviour of clay minerals.