Net-shape forming of ZrO2-based ceramics and the effect of shaping process on superplastic deformation

摘要

In this study, a slip casting method was used for the production of tensile specimens for superplastic deformation from zirconia powders containing 3 and 8 mol% yttria. It was seen that the slip casting process allowed the production of complex, net-shape and economical production of a relatively small number of individual shapes. The factors affecting the casting characteristic of the slip system, namely, solid content, slip viscosity, dispersing agent concentration and moulding conditions were investigated and optimum values for the above were determined. The effect of shaping process on superplastic deformation was also investigated for slip-cast and die-pressed specimens. It was seen that superplastic ductility obtained from slip-cast specimen was higher than that of die-pressed one. The reason for ductility enhancement was due to the homogeneous dispersion of the powder and elimination of agglomerates in slip-cast specimen, compared to die-pressed specimen in which agglomeration caused non-homogeneous sintering leaving crack-like voids responsible for early fracture. (C) 2001 Kluwer Academic Publishers. [References: 18]