The effect of slip casting parameters on the ultrafine microstructure and density of pore-free YAG ceramic obtained by vacuum sintering

Abstract

In this study, the effect of slip casting parameters on the ultrafine microstructure and the density of pore-free YAG ceramic was evaluated. A stable, high concentrated aqueous YAG slurry using Dolapix-CE64 as a dispersant was prepared and the effect of dispersant concentration as well as the solid load on the stability and rheological behavior of the slurry was also studied. The optimum dispersant content for the suspension was 1.5 wt% which led to the slurry with minimum viscosity and near-Newtonian behavior. The results showed that increasing the solid load of the YAG slurry causes higher viscosity and alters the rheological behavior of the slurry to a slight shear thinning. By increasing the solid load of the slurry up to a specific amount of 75 wt%, relative green density of the slip cast sample was increased to about 65%, but further increase reduced the green density. The microstructure and the density of the sintered body in the air and vacuum atmospheres comprise a direct relationship to the green density of the slip cast body.