Rapid starch consolidation of red clay-based ceramic slurry under simultaneous pressure-cooking and microwave irradiation

This study presents a simultaneous application of pressure cooking and microwave irradiation to consolidate ceramic slurry as a rapid shaping technique. The ceramic slurry, composed of red clay, feldspar, quartz and water, was solidified with the gelatinization of starch under varying heating conditions inside a domestic microwave pressure cooker. It was found out that, for a small amount of ceramic slurry, a shortest heating time of 2.52 min was achieved at microwave pressure cooking conditions of 50% power level and target temperature of 60 °C. Based on these conditions, large shaped ceramic prototypes of different shapes were successfully formed using proposed empirical equations to determine a desired heating time at any power levels. The physical characterizations revealed that the physical properties of dried and fired ceramic bodies formed under microwave pressure cooking were better than that of the conventional counterpart. Microstructural investigation into the fired samples revealed larger void spaces in conventional sample than that in microwave pressure-cooked sample.