Effects of microstructure on the sky-green color in imitating ancient Jun glazes

抄録

The sky-green glaze of ancient Jun ware was successfully imitated with the addition of 4 wt % calcium phosphate for introducing the phosphorus (P) to the composition. Effects of the calcium phosphate contents on the chromaticity, precipitated phase and microstructure of sky-green glaze were investigated. Based on the analysis of colorimeter, XRD, FT-IR, XPS and SEM, a possible coloring mechanism was proposed to explain the variation of glaze colors with the increasing of calcium phosphate content. The results indicated that the addition of calcium phosphate contributed to increasing the content of calcium iron phosphate [Ca₁₉Fe₂(PO₄)₁₄] and the size of phase separation droplets in glazes. The formation of Ca₁₉Fe₂(PO₄)₁₄ decreased the ratio of Fe²⁺ to Fe³⁺ and the increased size of phase separation droplets weakened the structural color, which increased the L* and b* value of glazes. Therefore, the color of sky-green glaze got more green and white gradually.