LAUSR

A series of cobalt blue pigments, which were synthesized based on the chemical compositions of the blue pigments in Kangxi blue and white porcelain, were investigated by Co, Mn, and Fe K-edge and L-2,L-3-edge X-ray absorption spectroscopy to determine the oxidation states and species of the elements and to discern their impact on the blue color. The results reveal that Co is bivalent and mainly located at tetrahedral sites, which is the main parameter controlling the blue color. Mn is mainly present as Mn2+, or CoxZn1-xAl2O4 and Fe is mainly present as Fe3+. In particular, Fe3+ substitutes the Al in CoAl2O4 and occupies octahedral sites with a high Mn content. All the synthetic cobalt blue pigments can form a solid solution with various end-members or an intermediate solution spinel. The spectroscopic determination of the oxidation states and speciation of Co, Mn, and Fe furthers understanding of the coloration of blue pigments in blue and white porcelain.