Study on the halo dispersion mechanism and glazing process of ancient blue and white porcelain of China

摘要

Element composition, micro morphology and crystal structure of blue and white porcelain was tested using scientific and technological means including x ray fluorescence, x ray diffraction and polarisation optical microscope analysis, respectively. Other kinds of porcelain were also tested as comparisons in order to explain the halo dispersion of blue and white porcelains. According to the results, dispersion diffusion layer between pigment and glaze is the cause of halo dispersion, generating a distinctive visual effect. Anorthite crystals are not the dispersion reason as there are also free anorthite crystals in blue and white porcelain without halo dispersion. In addition, the crystallisation rule of ancient ceramics was also summarised. Ceramic bodies with high alumina content tend to promote the growth of anorthite crystals from body to glaze. In Zhangzhou kiln porcelain, the fusion of colour and glaze is smooth, and the comparison with imitation samples demonstrates that the process of glazing before colouring may be adopted in parts of ancient blue and white porcelain, which is the so-called in-glaze colour process.