Glass-ceramic glazes for future generation floor tiles

Glaze in the CaO-MgO-Al2O3-SiO2 system was heated at 950-1190 degrees C for 2 h and characterized. X-ray diffraction showed that only -brace amount of mullite was formed in the glass-ceramic glaze heated at 950 degrees C. Both mullite and alpha-cordierite were formed in the glass-ceramic glaze heated at 1050 degrees C as primary and secondary phases. Glass-ceramic glazes heated at 1120 degrees C and 1190 degrees C contained alpha-cordierite and mullite as major and minor phases. Rietveld analysis revealed that the amount of alpha-cordierite increased and mullite decreased with increasing heating temperature. Field emission scanning electron microscopy showed presence of mullite crystals dispersed within residual glassy phase in the glass-ceramic glazes heated at 950 degrees C and 1050 degrees C. In the microstructures of glass-ceramic glazes heated at 1120 degrees C and 1190 degrees C alpha-cordierite crystals were mainly appeared. Energy Dispersive X-ray analysis corroborated X-ray diffraction results. Vickers rnicrohardness measurement demonstrated highest hardness (8.38 1 0.07 GPa) of the glass-ceramic glaze heated at 1190 degrees C. (C) 2012 Elsevier Ltd. All rights reserved.