Mullite-based refractories fabricated by foam casting

The research on the structure, behaviour and properties of mullite foams is strongly motivated by industrial demands for high-temperature applications. Sintered mullite foam stabilized by strontium aluminate is an appropriate candidate for industrial refractory applications under elevated temperatures. The preparation technique is based on casting of foamed kaolin slurry using air/surfactant sacrificial fugitive. Wet foam precursors were dried and treated to the temperature of 1250 °C. High-temperature behaviour and bulk properties of obtained products with the porosity up to 85% were characterised by means of high temperature X-ray diffraction analysis, thermal analysis and scanning electron microscopy. The mechanical properties and the thermal conductivity of sintered mullite-based foams were determined to be in the range from 1.7 to 2.5 MPa and from 0.05 to 0.06 W/m K, respectively.