Thermal Diffusivity/Conductivity of Magnesium Oxide/Silicon Carbide Composites

SiC-particle-reinforced MgO composites have been fabricated by hot pressing, and the thermal diffusivities of the composites measured in the temperature range 200–1000°C using a laser flash technique. The thermal conductivity of the composites was calculated by multiplying the diffusivity with density and with heat capacity. The Eshelby inclusion model has been examined, and an equation suitable for particulate composites with porosity has been derived using the multiphase Eshelby model. The model also considers the interfacial thermal condition. Good agreement was obtained between the predictions and the experimental results of the thermal conductivity of the composites, even for various levels of porosity in the composites. Crystal defects, observed in the composites, influenced the thermal conductivity, resulting in a deviation from isothermal interfacial condition. This was reflected in the interfacial thermal parameter,β used in the modeling, and the predicted value of β was in the range of 3–10, depending on the thermal conductivity of SiC used for the calculations.