Efficient composite dispersants for high solid content, low viscosity nano-zirconia slurries: An experimental and molecular dynamics simulation study

An effective dispersant is essential for creating a high-quality water-based ceramic suspension. When the solid content of the slurry is high, a single dispersant proves inadequate. This study proposes a strategy for producing nano-YSZ (yttria-stabilized zirconia) ceramic slurries with high solid content and low viscosity using compound dispersants ammonium polyacrylate (PAANH4) and fructose. The efficacy of dispersion is evaluated through rheological experiments and zeta potential analysis. The optimal dispersant effect is achieved when the compound dispersants are added in the following proportions: PAANH4 = 0.5 wt% and fructose = 5 wt%. Consequently, the viscosity of the nano-YSZ slurry, with a solid content of 50 vol%, is reduced to 696 mPa·s at a shear rate of 100 s−1. Both PAANH4 and fructose effectively lower the slurry's viscosity via two separate mechanisms: electrostatic-steric stabilization and increasement of free water content. Molecular dynamics (MD) simulation was utilized to examine the nanoparticle dispersion process. The results show that after adding dispersants, the distance between two equilibrium particles is 4 nm, and the potential mean force curve displays a clear energy barrier. This provides a new method for investigating the dispersion effects of dispersants.