Study On High-quality Low-temperature Alkali Borosilicate (ABS) System Frit

Pollution free low temperature frits of alkali borosilicate (ABS) system have high thermal expansion coefficient (TEC) and poor corrosion resistance, they also have the disadvantages of low glossiness and bad coloration when used as the frits for ceramic on-glaze pigments. In order to overcome these inherent drawbacks of frits of ABS system, rational designing of frits composition therefore optimizing their performance were carried out in this study in an attempt to prepare high quality low temperature frits of high glossiness and low thermal expansion, thereby improving the corrosion resistance of the ceramic decorative materials, especially alkali resistance.Experiments of different SiO2/B2O3, SiO2/Al2O3and B2O3/Al2O3ratios, mixed alkali metal oxide, and the effect of zirconium silicate were carried out to investigate their influences on the performance of frits of ABS system. The frit samples were characterized by SEM, FT-IR and dilatometry with special emphasis laid on the influence of each component of the ABS system on the chemical stability, glossiness and thermal stability of the as-prepared frits.Result of adjusting the silicon-boron, aluminum-silicate and boron-aluminum ratios showed that when the values of n(SiO2)/n(B2O3), n(SiO2)/n(Al2O3) and n(B2O3)/n(Al2O3) lie in the range of1.6～2.4,8～8.7and4.4～5.6, respectively, the resulting frits are of high chemical resistance, high glossiness and low TEC.Result of Li2O-Na2O mixed alkali experiments indicate that frits obtained when introducing6%～8.92%Na2CO3have higher chemical resistance than that of the ones resulting from the adjustment of SiO2/B2O3, SiO2/Al2O3and B2O3/A12O3ratios. But the former ones have a slight decrease in glossiness and a large increase of TEC compared with the latter ones. The experiments of K2O-Na2O mixed alkali showed that the frits have high chemical resistance, high glossiness and low TEC when introducing8.7%to14.39%albite. In general, the samples resulting from Li2O-Na2O mixed alkali have better performance than that of the ones resulting from K2O-Na2O mixed alkali.Introducing additional zirconium silicate is the most effective way to improve the corrosion resistance, the appropriate dosage is of1.5%to3%. The resulting frits have the strongest chemical resistance, little variations in glossiness and, to some extent, the decrease of TEC compared with the above series.The as-prepared frits, in this study, were mixed with the on-glaze cobalt blue colorant to prepare pigment followed by decoration firing. The samples are of pure and bright coloration and the performance of alkali resistance basically complied with the test standard of European Union dishwasher-resistance.