Reformulation of an Aqueous Alumina Slip Based on Modification of Particle‐Size Distribution and Particle Packing

Six alumina casting slips with particle‐size distributions varying from 44 to 0.1 μm were examined. Particle packing was calculated using the approach of Andreasen. Viscosity, green density, and pore‐size distribution were measured. It was found that contouring the intermediate size distribution for particles finer than 15 μm provided the most desirable viscosity for slips composed of wide size distributions. For slips containing 50 vol% solids, the lowest viscosity obtained was 196 × 10⁻³ N · s/m² (with a two‐component size distribution), and a green density of 2.52 g/cm³ (65% of theoretical) was achieved with a ternary system. These casts had bimodal pore‐size distributions centered around approximately 1 and 0.1μm.