Property characterization and numerical modelling of the thermal conductivity of CaZrO3-MgO ceramic composites.

Three composite materials with different CaZrO 3 /MgO fractions (2/3, 1/2, 1/3) and two single-phase materials (CaZrO 3 and MgO) were fabricated and their thermal conductivity was investigated. Complete thermal and mechanical characterizations (thermal expansion coefficient, thermal diffusivity, specific heat, hardness and toughness) of the materials were performed. Values of the thermal conductivity up to 480 °C of the composites were compared with those calculated with the main analytical models. From the real microstructures of the three composites, representative volume elements (RVE) were built and used for finite element modelling (FEM) of thermal conductivity using conductivities of the single-phase materials as inputs. The FEM results showed no differences for the 3 spatial directions of the RVE, nor for the different edge lengths (11, 14 and 17 μm). Results of all analytical models are statistically different from the experimental ones, being those from the Bruggeman model the closest. Results of the proposed FEM are statistically coincident with the experimental ones, showing sensitivity to temperature variation. [ABSTRACT FROM AUTHOR]