Porosity dependence of thermal conductivity of ceramics and sedimentary rocks

Abstract

The connected grain model of porous ceramics, developed earlier to explain porosity dependence of the elastic modulus, is extended to study thermal transport. The porosity and grain-size dependence of the thermal conductivity is calculated in terms of a power law. The exponent of the power law is dependent on the skewness of the grain-size distribution. The formalism is compared with the experimental results for isometric spherical-pore distribution in alumina, random-pore distribution in alumina, uranium dioxide and yttria-stabilized zirconia, sedimentary rocks and bricks. Good agreements are found between the experimental results and theoretical predictions based on the microstructure of the materials and their porosity dependence of the elastic modulus.