Fabrication of Silicon Nitride Parts by Slip Casting

Slip casting is a suitable forming technique for achieving complex shapes, starting from ultrafine silicon nitride powder. The most important step of this technique is the deflocculation of the slip. This is made particularly critical in the case of silicon nitride by the addition of more or Jess complex sintering aids to the starting powder. A methodology for the study of deflocculation is presented. It is based on poten-tiometric analysis, viscosity measurements and sedimentation experiments. The influence of pH and the effect of deflocculants are discussed in conjunction with slip-casting results.