Seven glaze compositions for porcelain, in which 0 to 15 wt% of the feldspar in the base glaze composition is replaced by boron zirconium frit were prepared. The glaze batches were ground in a ball mill until the residue on a 45 um sieve was 0.5wt%. The glaze was applied by spraying to unfired 120x120mm ceramic tiles prepared from sanitary porcelain slip. Samples for determination of fluidity & coefficient of thermal expansion were made. The samples were fired in industrial tunnel kiln at temperature of 1180C over a 12 h cycle. With increasing boron-zirconium frit quantity the whiteness & the fluidity of the glazes were raised to a maximum whiteness of 92%. The coefficient of thermal expansion values initially decreased & then increased as the amount of zirconium-boron frit was increased.
