Metal and oxydes in lustered ceramic: TEY and TFY-XAS to study and map the distribution of Cu and Ag in Renaissance Lusters

Lustered ceramic are famous for their characteristic iridescence metallic-like surface. These samples are made of a ceramic biscuit covered with a white or colored glaze. In certain areas, the glaze is covered also by a luster layer, which is made of metallic (Ag and Cu) nanoparticles. This layer is a few tens of nanometers thick and lays on top of the sample, just below a thin layer of SiO2. The production technique and the layer structure of these samples are complex and follows the technology invented in the Middle East in the IX century and developed later in Egypt and Spain which requires a second firing in oxydizing and reducing atmospheres. Here we want to perform XAS measurements in TEY and TFY to study the different oxydation states of Cu and Ag in surface and deep inside the sample, distinguishing between lustered and non lustered areas.