Modelling thermal conductivity of biphasic ceramic materials by the finite element method

The thermal conductivity of two-phase ceramics has been modelled by finite element method for a wide range of second phase contents, aspect ratios and thermal conductivities of the filler phase. The finite element method model has been validated with the experimental thermal conductivity data from exemplary ceramics to show the applicability of this model, namely alumina/silicon carbide composites and highly porous mullite materials, which show second phases of very different thermal conductivity (SiC and pores). The selection of the mesh element dimensions has been based on a schematic picture of the microstructure. For the first time, the finite element method simulation of a large number of random biphasic meshes has been used for estimating errors in the predicted thermal conductivity values that were comparable with the experimental error. The model can be very helpful in designing new materials with specific thermal conduction, limiting the more expensive and time consuming material preparation work.