Full-field XANES analysis of Roman ceramics to estimate firing conditions—A novel probe to study hierarchical heterogeneous materials

Roman black gloss ceramics from two different locations and separated by 50–80 years were investigated by X-ray absorption near edge structure analysis in full field hard X-ray transmission microscopes. These spectro-microscopy measurements were complemented by Raman spectroscopy, and X-ray diffraction spot analyses to gain insights into possible differences in manufacturing technology. Our results indicate that the two vessels underwent significantly different firing protocols, suggesting that there was a surprisingly quick evolution of a complex technological process in response to changing needs and tastes of a burgeoning empire. Furthermore, our results show that the ability of the full field X-ray spectro-microscope to investigate large sample areas (from hundreds of µm2 to as much as 2 mm2) with high spatial resolution (of 300 nm down to 30 nm) together with its ability to correlate sample porosity (derived from tomography) with the distribution of chemical phases makes it an invaluable tool in the investigation of nanoscale processes in hierarchically heterogeneous chemical systems—from Roman ceramics to some of the most advanced technological products of today.