Nanoparticle Chemistry Revealed in Abbasid Ceramic Luster

Researchers have identified the chemical reactions that enabled ninth-century Abbasid potters to produce golden, red, brown and yellow ceramic glazes with a metallic, iridescent appearance. The study, led by scientists at Universitat Politècnica de Barcelona and the European Synchrotron Radiation Facility (ESRF), used synchrotron techniques to examine tiny fragments of historical ceramics and showed that the colors arose from silver and copper nanoparticles embedded within the glaze.

Polychrome luster was created by painting a glazed ceramic surface with a mixture containing metallic compounds, notably silver and copper. During firing, those elements diffused into the glassy coating and underwent reactions that included reduction, forming metallic nanoparticles in a thin surface region. The particles were not merely deposited on top of the ceramic: they became integrated into the glaze, producing a nanostructured layer whose composition and morphology controlled how it interacted with light.

The investigation combined X-ray spectroscopy and X-ray fluorescence at the ESRF’s ID21 beamline with X-ray diffraction at the ALBA synchrotron. According to the researchers, the microscopic beam and the ability to examine iron, copper and silver were essential for resolving the chemistry of the luster layers. The analysis found that luster formation involved an ion-exchange process in which copper and silver ions moved from the painted layer into the glaze and replaced alkali ions.

Firing conditions were crucial to this exchange. The luster had to be heated to a temperature between the glass-transition temperature and the point at which the glaze softened, conditions that favored ionic diffusion while helping prevent the painted material from sticking to the glaze. The final appearance was not determined simply by whether silver or copper was present, but by their relative proportions and their interactions with other elements in the glaze. The researchers reported that differences among luster colors primarily reflected different amounts of copper and silver, which affected the types, amounts, distributions and sizes of the resulting nanoparticles.

Marine Cotte, an ESRF scientist and co-corresponding author of the Science Advances paper, said the findings explain a manufacturing process that remains difficult to reproduce today. The study was based on fragments from historical ceramics, so the next phase will involve producing mock-up samples to separate the effects of individual manufacturing parameters. The researchers also plan to investigate the roles of other metals, including iron and tin, in luster formation. The results provide a chemical explanation for how a technology associated with the Abbasid period and later spread across the Islamic world generated its distinctive colors and metallic appearance long before the modern development of nanotechnology.

Subject of Research: Experimental investigation of nanoparticle formation in ninth-century Abbasid polychrome ceramic luster.

Article Title: Unveiling how nanoparticles create iridescence in ancient ceramics

Article References: Unveiling how nanoparticles create iridescence in ancient ceramics. Original publication (Bibliographic details unavailable.)

Image Credits: AI Generated

DOI: Not provided

Keywords: Abbasid ceramics, polychrome luster, nanoparticles, silver nanoparticles, copper nanoparticles, ion exchange, ceramic glaze, X-ray spectroscopy, nanotechnology, Unveiling, create, iridescence