Study on the Five dynasty sky-green glaze from Yaozhou kiln and its coloring mechanism

This work takes the Five dynasty sky-green glaze of Yaozhou kiln as the major study object. Based on the analysis of XRF, XRD, XPS and SEM/EDS, the chemical compositions, firing technique and microstructure of the sky-green glaze were investigated. A possible coloring mechanism was proposed to explain the variation of glaze appearance. The results indicated that the Five dynasty sky-green glaze had relatively high contents of CaO and K2O, which led to the better gloss and transparency than others. Besides that, the chemical coloring of Fe2O3 and the scattering of phyical structures also affected the color saturation and opacity of glaze surface. The high Fe2+/Fe3+ ratio and phase separation droplets of forming structural color by the amorphous photons and Rayleigh scattering contributed to increasing the blue tone of sky-green glaze. In addition, the residual crystals decreased the transparency of glaze surfaces.