Synchrotron XAS study of Mn and Fe in Chinese blue-and-white Ming porcelains from the second half of the 15th century

The XAS analysis of a blue-and-white Ming porcelain's decorations has been used to elucidate the porcelain's production technology. The porcelain exhibits the typical blue decorations with dark spots that are constituted by dendritic aggregates enriched in Mn and Fe. The XAS revealed that during firing Mn2+ and Fe2+ ions diffused into the glaze and started to crystallize at 900 °C as rhodonite and hausmannite-jacobsite intermediate compounds. The study of the Fe XAS pre-edges provided to be a powerful tool to assess the redox record from the porcelain. The natural basalt calibration determined the Fe3+/ƩFe × 100 in the glaze and confirmed the oxidizing conditions during its production. Hence, the obtained XAS helped to elucidate the temperatures at which the wares were produced by identifying the porcelain's pigments and the redox conditions during their production. This novel approach can also be applied on a broad range of modern and archaeological ceramics to elucidate their production technology.