مرکز منطقه ای اطلاع رساني علوم و فناوري - The Role of Quartz on Stain Resistance of Porcelain Tiles Based on Spodumene

Abstract :

Porcelain tiles characterized by a large quantity of glassy phase, low porosity are basically produced from clays, kaolinite, feldspars, and quartz. Clays and kaolinites provide plasticity and dry mechanical strength and form mullite and glassy phase during firing; feldspars are low-temperature glassy phase formers; and quartz contributes to thermal and dimensional stability, due to its refractoriness property. However, quartz significantly affects triaxial porcelain properties. The difference between the coefficients of thermal expansion of the quartz and the glassy matrix has a strong effect by subjecting the glassy matrix to microscopic residual compressive stress. The magnitude of these stresses produces cracks around the quartz particles, which may exceed a critical size, thereby causing partial stress relaxation and increasing microstructural damage leading to particle detachment. This microstructural damage adversely affects the product’s mechanical behaviour and stain resistance. In this study, in order to enhance the stain resistance of the porcelain tiles containing spodumene (max 2 wt %) substituted by Na feldspar it was prepared to compositions without quartz content. The results showed that it was obtained an increase in stain resistance of porcelain tiles without quartz by forming a low viscosity liquid phase during firing with a decrease in both closed porosity and average pore size, also increasing bulk density and mechanical properties.