Dispersion of concentrated aqueous yttria-stabilized zirconia with ammonium polyacrylate

The dispersion of concentrated 0.53 mu m yttria stabilized zirconia (YSZ) aqueous slip to achieve sintered compacts with high and uniform microstructure was investigated. 78 wt.% (37.5 vol%) and 83 wt.% (45.3 vol%) slips were prepared by dispersing the powder in water with ammonium polyacrylate (NH(4)PA) at pH values in a range of 8-9.5. The influences of the amount of NH(4)PA and pH on the rheological properties of 78 and 83 wt.% slips were studied. The minimum viscosities of 78 and 83 wt.% slips were obtained with the addition of 0.05-0.1 wt.% NH4PA at pH 9. Increasing pH from 8 to 9.5 had no effect on the YSZ dispersion with NH(4)PA. These dispersions yielded green densities of 63% of theoretical density (TD) and sintered to 98% TD at 1400 degrees C. (C) 2006 Elsevier Ltd and Techna Group S.r.l. All rights reserved.