Solubility parameters for ensuring a castable design in the Al₂O₃-based gel-casting system

Abstract

Gel-casting of ceramics is useful in fabricating near-net-shaped ceramic products owing to the use of a high solidloading-slurry and fast curing. However, the affinity between the precursors, which can affect the viscosity of the slurry, has not been discussed or optimized using different slurry-compositions. This study proposes a novel approach to estimate the affinity between the precursors by investigating the solubility parameters (SPs) of the precursors as a function of ceramic powder, monomer, and cross-linker of the ceramic slurry in a gel-casting system. Properties of the ceramic slurries and void-structures were examined systemically by altering the molecular structure of the monomer and composition ratio of the monomer and cross-linker. The SP of the precursors exhibited a good correlation with the slurry-viscosity, porosity, and defect-volume, which play important roles in determining the mechanical strength of a sintered body.