Effects of pore size on electrical and thermal properties of porous SiC ceramics

Porous SiC ceramics with three different pore sizes (similar to 7, similar to 45, and similar to 98 mu m) and two different porosities (similar to 54% and similar to 63%) were prepared to investigate the effects of pore size on electrical and thermal properties of the porous ceramics. With an increase in pore size from similar to 7 to similar to 98 mu m at the same porosity (similar to 54%), the electrical and thermal conductivities of the porous ceramics increased from similar to 1.01 to similar to 2.30 omega-1 center dot cm-1 and similar to 14.3 to similar to 26.2 W center dot m-1K-1, respectively. Similar trends have been obtained in the ceramics with similar to 63% porosity. The porous SiC ceramic with larger pore size has smaller pore/strut interface area at the same porosity, which leads to less carrier scattering and phonon-pore scattering at the pore/strut interfaces, resulting in higher electrical and thermal conductivities, respectively. These results suggest that the electrical and thermal properties of porous SiC ceramics can be successfully tuned by adjusting the pore size and porosity depending on the application.