Aqueous slip casting and hydrolysis assisted solidification of MgAl₂O₄ spinel ceramics

Abstract

This paper reports on synthesis of MgAl₂O₄ spinel (MAS) powders with six different chemical compositions and the consolidation of the synthesised MAS powders following an aqueous slip casting and hydrolysis assisted solidification (HAS) routes. The synthesised MAS powders were surface passivated against hydrolysis before being dispersed in distilled water to obtain suspensions with 41-45 vol.-% solid loading using suitable dispersing agents. In the case of the HAS process, the consolidation of suspensions was achieved in non-porous moulds under ambient conditions by the incorporation of AlN equivalent to 1-5 wt-%Al₂O₃ into the suspension. The stoichiometric MAS powder consolidated by slip casting and dry pressing routes was sintered along with those consolidated by HAS route at 1550-1650°C for 1 h. Various characterisation techniques were utilised to evaluate the effect of composition and consolidation technique on slurry characteristics and sintered properties of MAS ceramics.