The aim of the present work was to identify the conditions for the preparation of stable SiC slurries for fabrication of slip cast object and to correlate the slurry properties to the final properties of the ceramics. An ammonium salt of polymethacrylic acid was used as dispersant for SiC slurry. The effects of dispersant concentration and pH on the rheological behaviour of SiC suspension were studied. The slurry stability was evaluated by measuring settling of the powder as a function of time. The addition of dispersant improved the dispersion by increasing the negative zeta potential of SiC particles. The best conditions of stable slurry were selected on the basis of low viscosity and minimum settling of the powder. It was observed that 1 wt% dispersant resulted lowest viscosity for the slurry of 70 wt% solids loading. The properties of the slip cast object were compared with powder pressed object and it was observed that slip cast object exhibited better mechanical strength due to homogeneous powder packing.

Keywords: Colloidal suspension; Dispersant; Rheological study; Slip cast; Mechanical property