Development of Glaze with Alkali Free Frit

Abstract

The term glaze can be defined as a thin layer or coating that is used to coat or seal the ceramic substrate. The glazed ceramic product gives high strength, 0% porosity, good chemical resistant, color, hardness, resistant to chemical attacks, high thermal shock resistant, glossiness, whiteness and decorate. Because of all these characteristic and properties in ceramic glazes which makes glaze useful for the various field such as electrical, chemical, mechanical, tile applications, tableware, sanitary-ware and refractory applications. In most cases of glazes to tile applications the major problem faced is defect like crazing and peeling due to presences of alkalis ions in the glaze composition which can be cured by developing an alkali-free glass system for glaze composition. For the present work an alkali-free glass system with composition 65% SiO2, 25% B2O3, 6% Al2O3, 2%CaO and 2% MgO (in wt %) has been prepared by melt quenching method. The melt quenched glass used as frit for glaze preparations. Two different type of clay bentonite and ball clay have been used in glaze compositions. The amount of bentonite and ball clay has been varied from 1%, 5% and 10%. DSC and TG, Dilatometry, FTIR analysis have been done for the alkali-free glass powder to characterize it. The maturity of glaze had been determined by firing glaze samples at 1050oC, 1100oC, 1150oC, 1200oC, 1250oC and 1300oC. Six glaze compositions have been prepared and applied on the tiles. DSC and TG, Dilatometry, flow test and sieve analysis have been done for all glaze compositions. Vickers hardness, thermal shock resistance and crazing test have been done for glazed samples