Electron microscopy study of Hispanic Terra Sigillata

Two Hispanic Terra Sigillata pottery samples from different workshops – Tricio and Andújar – have been characterized by means of electron microscopy and associated techniques and X-ray diffraction data. The combined information from transmission electron microscopy images, electron diffraction patterns and microchemical analysis has revealed the nature and distribution of the precipitates of the ceramic piece slip, which is a very important part in the characterization of these kind of ceramic wares. Both samples present homogeneously dispersed α-Fe 2-x Al x O 3 (corundum-type structure) particles embedded in a glassy matrix of SiO 2 -Al 2 O 3 . The Si : Al ratio of the matrix is different in each case, with a higher Al content in the Andújar ceramic sample. Crystallites of spinel – Mg(Al,Fe) 2 O 4 – and Al 2-x Fe x O 3 are also detected in both cases. In addition, ilmenite phase (FeTiO 3 ) and TiO 2 (rutile-type) were observed less frequently.