Analyzing the Chemical Compositions of Co-Based Materials in Blue-and-White Porcelains from the Yuan Dynasty

Abstract The blue-and-white porcelains from the Chinese Yuan Dynasty include different ornamentation effects, such as bow string and main patterns. In this study, ten pieces of blue-and-white porcelains from the Jingdezhen Ceramic University Museum were examined using energy-dispersive X-ray fluorescence to reveal the chemical compositions of their microzones. Three key findings were obtained. First, the Co-based material used in the specimens was imported ore with high Fe and low Mn contents, with certain amounts of Ni and As. Second, the bow-string and main patterns had different (Fe + Mn)/Co ratios; the main patterns had lower ratios, suggesting a purer Co material. Third, the differences in the elemental ratios were verified against a historical purification process, whereby the main pattern was speculated to be painted with purified Co-based materials. Finally, the material differences that began to appear during the Yuan Dynasty, which influenced the painting of blue-and-white porcelains in the Ming and Qing dynasties, were investigated. This study provides a new perspective on the blue-and-white porcelains from the Yuan Dynasty and the development of decoration systems for Chinese blue-and-white porcelain paintings.