Wicking Technique for Determination of Pore Size in Ceramic Materials

A technique is described for the measurement of mean pore size in ceramics by wicking. Pore size is derived from the measured rates of capillary rise of several apolar, low‐energy liquids of known surface tension through thin slices of porous materials, via the Washburn equation. The use of apolar, low‐energy liquids assures that the contact angle θ=0° (and cos θ= 1) so that the mean pore radius, R, is the only unknown in the Washburn equation. Fore‐size data are presented for two colloidal gel compositions with engineered pore‐size distributions. Pore diameters obtained from wicking are found to be smaller than those afforded by merciury porosimetry by a factor of ∼2.