Shape Forming of Alumina by Step Pressure-Vacuum Hybrid Slip Casting

Abstract

Conventional methods for preparing ceramic bodies, such as cold isostatic pressing, gypsum-mold slip casting, and filter pressing are not completely suitable for fabricating large and thick ceramic plates, because of disadvantages such as the high cost of equipment, formation of density gradient, and differential shrinkage during drying. These problems could be avoided by employing step pressure-vacuum hybrid slip casting in which consolidation occurs not only by the compression of the slip in casting room, but also by vacuum sucking of the dispersion medium (water) around the mold. This method enabled us to fabricate a 110 × 110 × 20 mm alumina plate without cracks and with homogenous density, and the possibility of extending the method to fabricate other ceramic products appears to be promising.