Frit or glaze contg. calcium titanium silicate as opacifier - to obtain dense opaque white glaze which does not discolour

摘要

The opacifier has compsn. CaTiSiO5 (CTS), and is used esp. to produce white opacity. The CTS is pref. crystalline, obtd. by recrystallisation from the vitreous phase of the glaze, esp. to obtain CTS particles below 0.1 mu m in size. The pref. opacifier added to a frit or glaze consists of crystalline CTS with size 1 mu m. The CTS is pref. made from a frit contg. TiO2:CaO:SiO2 in molar ratio 1:1:1, which dissolve in the mother phase when heated, after which the frit is quenched and reheated so that crystals of CTS are formed above 500 degrees C. They crystals are next heated to form a transparent, homogeneous melt, which is then quenched. This opacifier withstands a wide range of baking temps. used for ceramic objects and does not discolour on reheating nor due to other ions or impurities in the glaze.