Formation mechanism of titania based opacified glaze with novel core-shell nanostructure

摘要

The formation mechanism of titania based opacified glaze is discussed in this paper. The glaze system composed of albite, kaolin, talc, calcite, quartz, titanium dioxide and zinc oxide is used to adjust the glaze formula and to obtain the glaze samples with better opacifying effect. The whiteness and glossiness of glaze products formed with different TiO2 contents are characterized by whiteness meter and gloss meter respectively. The structure of glaze layer is analyzed by means of SEM, TEM and EDS. The results show that the introducing of TiO2 can promote the phase separation and forms the special Si-rich/Ti-rich core-shell nanostructure. During the cooling process of the glaze, the liquid-liquid phase separation occurs and results in the formation of uniform Si-rich nanoparticles. While the Ti-containing components are enriched at the interface between the different phases and a special spherical core-shell structure is obtained around the Si-rich nanoparticles. The glaze layer is filled with the core-shell nanospheres and shows a network structure like opal. However, due to the decrease of cationic content (Ti, Zn, Ca, and Mg) in the interface between glaze and body, the network nanostructure like reverse opal would be formed. In the interaction of special opal and reverse opal structure, the opacifying effect is enhanced obviously.