Porcelain: Convencional and Microwave Sintering

The porcelains are ceramics whose properties are strongly influenced by the microstructure developed after sintering. This microstructure can be changed, either by changing the composition as in the sintering conditions. New sintering methods, have allowed a greater control of the ceramics properties as a consequence of the final microstructure greater control. Microwave sintering is one of these techniques that have aroused a high interest in ceramics process because this method led to higher densification and the fine microstructure in much shorter time duration compared to conventional procedures. In this work it was studied the porcelain ceramics sintered under microwave and traditional heating conditions. Porcelains disks were prepared under a uniaxial pressure. One set of samples was sintered at in a conventional muffle furnace at range of 1250°C and 1300°C for 2 h. Another set of disks was sintered using a custom-made 2.45 GHz furnace at 1200°C temperature between 15 and 45 minutes. Density and microstructure information were obtained on microwave and convention processed samples by Archimedes principle and SEM (scanning electron microscope, JSM-5510 LV), respectively. Microwave sintering of porcelains promoted densification in much shorter time duration when compared to conventional method. The microstructure was strongly influenced by microwave heating, promoting an abnormal grain growth of the primary mullite.