PORE SIZES AND FILTRATION-RATES FROM 2 ALUMINA SLIPS

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.