YTTRIA-STABILIZED ZIRCONIA CRYSTALS: SYNTHESIS AND CRYSTAL STRUCTURE

An yttria-stabilized zirconium oxide crystal has been synthesized by the skull melting method. Gem-quality colorless and transparent materials is produced when 25wt.%Y₂O₃(stabilizer) and 0.04wt.%Nd₂O₃(decolorising agent) are added to the ZrO₂ powder. It shows vitreous luster with a slightly oily appearance. Under a polarizing microscope, the crystal shows isotropic nature with no appreciable anisotropism. Mohs hardness value and specific gravity is measured to be 8 and 5.85, respectively. Under ultraviolet light it shows a faint white glow. The crystal structure of yttria-stabilized zirconia has been re-investigated using single crystal and neutron diffraction methods. The symmetry is cubic with space group Fm3m and a=5.1552(5)A, V=136.99(5)A³, Z=4. The stabilizer atoms randomly occupy the zirconium sites and there are displacements of oxygen atoms with amplitudes of ~0.033 and 0.11 along <110> and <111> from the ideal positions of the fluorite strucrure, respectively.