CASTING CONDITIONS AND RHEOLOGICAL PROPERTIES OF Si//3N//4 BASED MATERIALS.

Casting behaviour and rheological properties are studied to define the appropriate conditions for preparation in the production of high temperature ceramics. Two different systems: Si-Si//3N//4-Al//2O//3-ZrO//2 and Si//3N//4-Al//2O//3-ZrO//2, are compared for different experimental conditions. Various quantities of solid phase and various types and quantities of deflocculants were tested. Some relations between particle size distributions, castability of the suspension, rheological properties, casting rate constant, porosity and texture of the green bodies were identified.