Non-destructive portable X-ray Fluorescence (pXRF) method for the characterization of Islamic architectural ceramic: Example of Saadian tombs and El Badi palace ceramics (Marrakech, Morocco)

Abstract

Archeological decorated ceramics from the Saadian tombs and El Badi palace sites (Marrakech, Morocco) have reached an advanced deterioration phase; the glazes have been increasingly weakened due to human and environmental impacts over time. Portable X-ray Fluorescence (pXRF) was performed in situ and on samples selected from these two monuments, in order to define the chemical agents responsible for the color of the studied glazed ceramics and to determine their evolution over time to help find answers and link between degradations and chemical compositions of different type of glazes. The results show that all samples are lead-silica type glazes with 25–59 wt% of PbO and 51 wt% of SiO2. The coloring agents used for the original glaze are conventional, copper (Cu2 + ) for the green color, iron (Fe3+) and manganese (Mn2+) for the yellow and black glaze. Phosphorus (P2O5), comes from carbonate mineral phases, is responsible for the blue opalescence of glazes. The study reveals that the ceramic industry has evolved recently in Morocco; elements such as calcium and potassium are currently used in small quantities while lead is increasingly used as flux in the glaze mixture. Iron and copper are still used for black, yellow and green colors, while the use of phosphorus has been replaced by other elements such as cobalt and copper.