The relationship between filtration rate and the resultant green body
microstructure was examined for aqueous alumina slips cast at two diff
erent deflocculation states. The volume loading of both slips was 40%.
SliP viscosities of 500 and 60 mPa-s were produced by different tetra
sodium pyrophosphate additions. The filtration rate of these slips var
ied by a factor of 2; however, mercury porosimetry results showed the
same average pore size for both samples. Single and multiple small-ang
le neutron scattering results showed the specimen cast with the higher
-viscosity slip to possess a bimodal pore size distribution. The body
cast with the low-viscosity slip showed unimodal porosity and, consequ
ently, the filtration is attributed to the toroidal region between the
packed particles. These results showed that mercury porosimetry does
not provide a pore size that predicts filtration behavior of slips wit
h different degrees of dispersion.