Densification Behavior of Single-Crystal and Polycrystalline Spherical Particles of Zirconia

Micrometer size polydispersed spheres of zirconia were produced via electrostatic atomization and pyrolysis of aqueous zirconium acetate-yttrium acetate precursors. Varying the precursor composition in the ZrO₂-rich region of the ZrO₂-Y₂O₃ binary system resulted in the production of either single-crystal (0 and 10 mol% Y₂O₃O or dense polycrystalline (3 mol% Y₂O₃) zirconia spheres of similar size distribution for densification studies. Powders of either the singlecrystal or the polycrystalline particles exhibited contrasting densification behavior; viz., powder compacts composed of polycrystalline particles obtained significantly higher endpoint densities than their single-crystal counterparts. Microstructural observations showed that while necks between single-crystal particles reached a stable size, necks between polycrystalline particles continued to grow.