CENTRIFUGAL SLIP CASTING OF ZIRCONIA (TZP)

Tetragonal zirconia (3Y-TZP) ceramic parts were produced via centrifug al slip casting. This forming method combines the advantages of wet po wder preparation with a very efficient densification technology to pro duce massive and near-net-shape ceramic parts. Aqueous TZP slurries wi th solids contents up to 42.3 vol.% and low viscosity were prepared us ing Darvan C as a deflocculant and ultrasonic cavitation to achieve a good homogenization. At solids loadings above 40 vol.% differential se gregation effects during centrifugation are negligible. Very good part icle packing with narrow pore size distributions (from r25=21.1 nm to r75=17.3 mm) were achieved. High green densities of up to 57% of theor etical density ( TD) were obtained after centrifuging at 4000 g for 90 min. High sintered densities (> 99.3% TD) were achieved at sintering temperatures as low as 1300-degrees-C with 2 h holding time. Sintered compacts have a very fine microstructure with an average grain size of 0.3 mum and narrow grain size distribution. Centrifugal slip casting has the potential to produce massive ceramic parts with reduced defect sizes and thus high reliability.