Influence of rheological behavior of aqueous Al2O3/nano-TiO2 slurry on the characteristics of powders prepared by spray pelletization

The rheological behavior of aqueous Al2O3/3 wt.% nano-TiO2 slurries and the powder characteristics prepared by spray pelletization were investigated in consideration of dispersant content, binder content and solid content. The rheological measurement results indicate that the slurry exhibits shear-thinning behavior, which is beneficial to the spray pelletization process for the composite ceramic powder. The slurry has the lowest viscosity when the contents of dispersant and binder are 0.3 and 1.0 wt.% of the solid phase, respectively. The viscosity of the slurry increases with the increase of solid content. When the solid concentration is about 60 wt.%, the slurry is optimized to have good dispersity and stability. Powders prepared by spray pelletization using the optimized slurry have good spherical shape and small size distribution so as to have good fliuidity and high loose packing density. The composite powders by spray pelletization can be applied in thermal spraying process.