Centrifugal casting of Al2O3-15 wt.% ZrO2 ceramic composites

Aqueous ceramic slurries with different solid contents (60, 70 and 78 wt.%) were prepared by mixing 85 wt.% low-temperature-sinterable high purity alpha-alumina and 15 wt.%ZrO2 (3 mol% Y2O3) in distilled water and a small amount of poly-carboxylic ammonium as the dispersion agent. Consolidation was performed by using a high-speed centrifugal casting process at 4000 rpm for 1 h. The result showed that the dispersion agent had a great influence on the viscosities of the slurries. It was also observed that the green and sintered densities of the Al2O3-15 wt.% ZrO2 composites increased with the solid contents. Phase segregation could be effectively eliminated when the solid content of the slurry was 78 wt.%. (C) 2002 Elsevier Science Ltd and Techna S.r.l. All rights reserved.