Porcelainized stoneware tiles have experienced many aesthetic improvements in the last few years, occasionally accompanied by some depletion of surface properties. The introduction of 5–10 mass-% of an easily devitrifiable glass frit leads to a significant increase in the white index of the ceramic body, simultaneously allowing a better exploitation of pastel hues colouring additives in bulk coloured porcelainized stoneware tiles. Optimum sintering temperature, densification, and water absorption of compositions with glass-frit addition are comparable to large-scale production porcelainized stoneware tiles. Moreover, when ceramic tiles are fired according to the typical industrial fast-firing cycle of 60 min up to 1200 °C, the flexural strength, indicated by the modulus of rupture measured values, benefits from glass-frit addition.
CaO-ZrO2-SiO2 glass-frit addition to porcelainized stoneware: enhancement of tiles colouring capabilities / Siligardi, Cristina; Veronesi, Paolo; Leonelli, Cristina; D., SETTEMBRE BLUNDO; G., Baldi; E., Generali. - In: TILE & BRICK INTERNATIONAL. - ISSN 0938-9806. - STAMPA. - 18:(2002), pp. 216-221.