Preparation of porous spodumene/zircon composite ceramics and its thermal and mechanical properties

Porous beta-spodumene/zircon (ZrSiO4) composite ceramics were prepared by addition of zirconia to spodumene mineral using conventional solid reaction methods. The formation of the zircon was investigated by means of the differential scan calorimetry measurements and an X-Ray diffractometer. The microstructure of the composite ceramics was observed through a scanning electron microscope. The results show that the presence of zircon benefited the formation and stability of the porous structure and improved significantly the thermal endurance and mechanical properties of the spodumene matrix. The composites with 10-15% porosity exhibit an excellent thermal shock resistance, a low thermal expansion coefficient of approximately 1.4 x 10(-6) K-1 in the range of 200-800 degrees C and a high flexural strength about 100 MPa. It is found that the spodumene/zircon composites, widely used as a high temperature structure material, can be synthesised by a cost effective method.