Comparison of different zirconia powders for slip casting of alumina–zirconia ceramics

Abstract

Two commercial 3 mol.-% yttria partially stabilised zirconia powders, 0?3 wt-%Al2O3 doped (Al doped Y-PSZ) and without Al2O3 (Y-PSZ), were used to produce alumina (Al2O3)–zirconia (ZrO2) slip cast composites. The effect of the substitution of Al2O3 and/or Y-PSZ by Al doped Y-PSZ on the rheological properties of concentrated aqueous Al2O3–ZrO2 slips was studied. In addition, the density of green cast samples was studied and related to the degree of slip dispersion. The viscosity and yield stress values of Al2O3 Al doped Y-PSZ suspensions were higher than those of Al2O3 Y-PSZ ones for all the compositions and solid loading studied. This behaviour could be explained by a larger effective size of the Al doped Y-PSZ particles, which resulted in a higher effective solid volume fraction and a lower amount of free liquid available for flow. The substitution of Y-PSZ by Al doped Y-PSZ in the Al2O3–ZrO2 mixtures resulted in a less dense packing of cast samples.