Slip casting of alumina powder mixtures with bimodal size distribution

Abstract

In order to increase the packing density of green compacts, using spherical alumina powder with a narrow particle size distribution as the coarse powder, a bimodal size distribution alumina powder mixture, of which the particle size ratio of the coarse to the fine powder was about nine, was compacted by slip casting. The green compact had a maximum relative density of about 78% and uniform packing structure when the particles were sufficiently dispersed and the alumina content in the slip was about 49 vol%. The relative densities of the green compacts were slightly higher than that of an isostatically pressed compact but they had very nonuniform packing structure when the alumina content in the slip was higher or lower than 49 vol%. It was considered that slips, in which the particles were well dispersed, the alumina content was relatively high and the fluidity was sufficiently maintained, should be prepared in order to obtain compacts with high relative density and uniform packing structure.