Optimization of the rheological properties of nanometer sized tetragonal polycrystal zirconia slurries for aqueous-gel-tape-casting processing

The aim of the present work was to identify the conditions for the preparation of stable zirconia slurries with high solid loading for the production of aqueous-gel-tape-casting objects with improved properties. Influences of the powder and dispersant on the rheological properties were investigated. The result indicated that the polyelectrolyte dispersant greatly affected the surface charge of nanometer tetragonal zirconia particle and the rheological behavior of nanometer sized polycrystal zirconia suspensions. For each factor there exists an optimum range in which low viscosity was achieved for slurry of high solid loading. The proper dispersant content is between 0.8 and 1.2 wt.%. The rheological behavior of high solid loading slurries is non-Newtonian flow-‘shear-thinning’ character as the shear rate is increased. The viscosity of the 77 wt.% powder loading slurry with ≈1.0 wt.% polyelectrolyte (based on the powder) was 750 mPa s at the shear rate of 48 s−1. The slurry at the optimum conditions met the demands of the aqueous-gel-tape-casting process.