Theoretical and experimental analyses of thermal conductivity of the alumina–mullite system

The thermal conductivity of the three phase system of alumina–mullite–pore was calculated by a theoretical equation developed in this research group, and compared with the experimental results. The pores in the sintered composite were treated as one phase. The measured conductivity of the composite with 0.5–25% porosity was in accordance with the theoretical prediction. No grain size effect of mullite particles on the thermal conductivity was measured in the range of 1–50 μm. This result is also explained by the developed model.