Effect of homogenizing procedures on the slip casting of reaction sialon suspensions

Reaction sialon suspensions were prepared using 3-wt.% KD1 (a polyester/polyamine condensation copolymer) as dispersant in organic media of 60-vol.% methyletheylketone and 40-vol.% ethanol. Different homogenizing procedures were used and compared, such as: high energetic planetary milling, low energetic ball milling and ultrasonic disaggregation. The effect of different homogenizing routes and solids loading on the rheology of suspensions and on the properties of slip casting green bodies has been studied. The differences observed among the various mixing procedures could be attributed to the different degrees of disaggregation and therefore to different fractions of surface coverage of the reaction sialon powders by the dispersant.