Effect of controlled capillary force variation on particle alignment and mechanical strength in slip-cast bimodal alumina

This study investigates how small, controlled variations in mould capillary force influence the microstructure and mechanical reliability of slip-cast bimodal alumina. Capillary pressure was systematically adjusted by varying the plaster-to-water (P/W) ratio of Plaster of Paris (PoP) moulds within a narrow range around the manufacturer's specification. The resulting changes in pore structure and wettability were quantified to calculate effective capillary stresses, which were then correlated with particle alignment and surface-dependent mechanical performance. Bimodal alumina containing large, platy particles was used to statistically track capillary-induced alignment during casting, while three-point bend testing assessed the strength and reliability of sintered bars loaded on the PoP-contact surface. Results show that capillary pressure varies nonlinearly with P/W ratio and that even