REN Zhao ¹, LIU Zijian ¹, SHI Pei ², WANG Fen ², ZHU Jianfeng ², LI Zhuling ³
(1. School of Design and Art, Shaanxi University of Science and Technology, Xi'an 710021, Shaanxi, China;
2. School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, Shaanxi, China;
3. Tongchuan Yaozhou Kiln Lijia Porcelain Workshop Co. Ltd., Tongchuan 727031, Shaanxi, China)

Abstract: The separative-phase celadon glaze similar to the ancient Jun glaze was successfully prepared using Cr₂O₃ as a colorant instead of Fe₂O₃ in traditional celadon together with calcium phosphate as a phase accelerator. The effects of the calcium phosphate content on the color and microstructure of the separative-phase celadon glaze were characterized by colorimeter, XRD, FT-IR, SEM, and EDS. Furthermore, the coloration mechanism of the separative-phase celadon glaze with Cr₂O₃ as a colorant was also analyzed. The results indicated that the crystal content in glaze melt increases with the introduction of calcium phosphate, which further enhances the opacity of the glaze. Meanwhile, the size of phase separative droplets in the glaze decreases and then darkens the blue opalescence caused by the Rayleigh scattering phenomenon. Both factors weaken the green color of Cr³⁺ and accelerate the glaze color transformation into dark purplish blue. However, the high content of hydroxyapatite crystals hinders the occurrence of the Rayleigh scattering with addition of excessive calcium phosphate. Therefore, the glaze color gradually turns bluish white.

Key words: chromium oxide; celadon; calcium phosphate; phase separation structure