A new mullite foamed ceramic prepared by direct-foaming methods in parallel with a mechanical activation technique

Abstract

Mullite foamed ceramics were prepared by direct-foaming methods in parallel with a mechanical activation technique (ball-milling process) using white clay and industrial alumina as raw materials. The effect of the alumina by the mechanical activation technique on the performances of the foamed ceramics was investigated by the XRD, SEM, micro focus X-ray computed tomography, and finite element simulation. The results showed that: the smaller particle size obtained by the mechanical activation technique was beneficial to decreasing the pore size by improving the viscosity of the slurry and increasing the sintering degree, and then improved the compressive strength of foamed ceramics. The finite element simulation further proved the denser struts were significant in improving the compressive strength of ceramics. A novel model combining thermal conduction and thermal radiation was put forward to predict the thermal conductivity of ceramics at high temperatures.