FEASIBILITY OF USING CORDIERITE CLASS-CERAMICS AS TILE GLAZES

Basic principles of fabricating tile glazes based on cordieritic glass -ceramics are explained. Glass compositions from the MgO-Al2O3SiO2 thr ee-component phase diagram have been melted with and without the nucle ating agent TiO2. Additionally, a sodium borosilicate glass that is co mmonly used in the the glaze industry has been wet milled, together wi th the previous compositions, to produce a coating slip. Studies are f ocused on the role of the nucleating agent and glassy formulation in t he crystallization of the glass-ceramic system using differential ther mal analysis, X-ray diffractometry, and scanning electron microscopy. When added to a borosilicate glass, only one composition is capable of crystallizing cordierite under a fast-firing cycle used for ''monopor osa'' production. The porosity of the glaze layer is sufficiently low and the crystal size is small to ensure good mechanical and chemical p roperties, The presence of cordierite crystals in the glaze should enh ance abrasion and acid resistance, in comparison to a traditional matt e glaze that contains mostly enstatite or diopside crystals.