Comparison of flash sintering and industrial firing of ceramic wall tiles: Microstructure and properties

Abstract The ceramic tile industry is energy intensive, characterized by long firing times and high temperatures. Therefore, flash sintering (FS), which greatly conserves energy by completing sintering in a few seconds at low temperature, is of interest to this industry. In this study, FS was applied for the first time to ceramic wall tile bodies. The experiments were carried out at a furnace temperature of 900°C, under an applied field of 100 V/cm, and current densities of 50, 100, 150, and 200 mA/mm 2 . The influence of process parameters on phase and microstructure development, and water absorption and hardness properties were investigated. These results are compared to the traditional industrial/conventional process (CP). It was observed that the reactions among the raw materials were completed in a few seconds during flash. The microstructure was similar to the CP specimens. Water absorption (9.55%–10.32%), porosity (19.06%–23.92%), and bulk density (1.94–2 g/cm 3 ) values were also found to be comparable. The bulk density increased and porosity decreased with higher current density. Besides quartz and anorthite, gehlenite phase was also detected in FS samples, which was absent in CP specimens. The hardness of the FS samples was approximately 25% lower than CP samples.