Synthesis and dispersion of yttria-stabilized zirconia (YSZ) nanoparticles in supercritical water

Yttria-stabilized zirconia (YSZ) nanoparticles were synthesized in supercritical water (SCW) without the use of mineralizers that are conventionally used to ensure basic conditions during synthesis. Process parameters were varied and their effect on the synthesis yield and particle morphology and composition were investigated. Conditions for synthesizing a stoichiometric YSZ nanopowder were identified. Dry YSZ particles collected in the continuous SCW process were redispersed in water in order to study their aggregation characteristics (including the size of agglomerates and the degree of agglomeration) in aqueous dispersions. Surface modification by the addition of polyethylenimine (PEI) was shown to result in stable dispersions of particles with average diameters between 50 nm and 100 nm.

► Demonstrates that yttria-stabilized zirconia (YSZ) nanoparticles can be synthesized at mild conditions (350–380 °C). ► Synthesis was achieved in supercritical water (SCW) in the absence of mineralizers. ► Demonstrates that aggregation of particles in aqueous dispersions can be minimized by the addition of polyethylenimine (PEI).