Development of diopside based wall tile glaze and engobes

In this study, opacity was achieved by diopside crystallization in fritsbelonging to the SiO2-CaO-MgO-B2O3-Na2O-K2O glass ceramic system. In thefirst part of the thesis, effects of compositional changes on thermal behaviour(sintering and crystallization processes), microstructure and optic properties ofglaze (L* index, brightness) were investigated in the diopside based frits. Studiesindicated that brightness and whiteness index are depend on the glazemicrostruture. Glazes which have higher than %40 crystal phase in itsmicrostructure, exhibit higher than 90 whiteness indexe. Frit compositions, whichcontain more than %12(Na2O+K2O+B2O3) by weight, exhibit brightness higherthan 40. Studies showed that roughness is another important parameter forbrightness. Glazes which have surface roughness less than 1,5 ?m, exhibitbrightness higher than 40. In the second part of the thesis; it was shown that highopaque engobes can be achieved by using diopside frits which has high sinteringand softening temperature. The studies also showed that by making compositionalvariations in engobe recipes; it is possible to control main properties of engobe(opacity, permability, thermal expansion coefficient). By new developed diopsidebased engobe frit and diopside based wall tile engobe, raw material costs havebeen reduced by ?%30 and ?%20 respectively.Keywords: Diopside, ,Glass Ceramic, Wall Tile Glazes, Engobe