LI2O-SIO2-AL2O3-MEIIO GLASS-CERAMIC SYSTEMS FOR TILE GLAZE APPLICATIONS

In order to verify the possibility of using glass-ceramic materials as tile coatings, the devitrification processes of three industrial formulations belonging to the Li2O-Al2O3-SiO2 glass-ceramic system were investigated by differential thermal analysis, X-ray diffractometry, scanning electron microscopy, and IR spectroscopy. Compositional variations were made by addition of large amounts of MgO or CaO or PbO (ZnO) oxides as well as through smaller additions of other oxides. In these systems the surface crystallization contributes appreciably to the bulk crystallization mechanism. All the systems investigated show a high tendency toward crystallization even at very high heating rates, developing a very close network of interlocked crystals of synthetic beta-spodumene-silica solid solutions (LiAlSi4O10). The results of this research are expected to establish the conditions under which these glass-ceramic systems can be practically used as tile glazes.