Transparent ceramics green-microstructure optimization by pressure slip-casting: Cases of YAG and MgAl2O4

This paper presents experimental data and its interpretation regarding the forming of YAG and spinel green-bodies, intended for transparent parts fabrication, by the pressure slip casting (PSC) method. Conditions for an optimal operation are established based on the modeling of the filtration kinetics. It emerges that the method is able to provide highly sinterable green parts by ensuring that the cakes porosity exhibits low average size and narrow size distribution. Results were compared with other popular forming approaches like slip casting (SC) and cold isostatic pressing (CIP). PSC was found as superior, to the other approaches, as far as obtainment of high sinterability green- bodies is concerned. In the case of YAG, it was shown that PSC method even allows the replacement of the traditional long vacuum firings by a two stage densification operation in which an initial air-firing is completed by a hot isostatic pressing step.