This facilitates moderate conductivity of yttrium-stabilized zirconia for O 2− ions (and thus electrical conductivity) at elevated and high temperature. Meaning that two Y 3+ ions generate one vacancy on the anionic sublattice. Thereby, oxygen vacancies are generated due to charge neutrality: Y 2 O 3 → 2 Y Zr ′ + 3 O O x + V O ∙ ∙ with = 1 2, Ionic conductivity of YSZ and its degradation īy the addition of yttria to pure zirconia (e.g., fully stabilized YSZ) Y 3+ ions replace Zr 4+ on the cationic sublattice. The thermal expansion coefficients depends on the modification of zirconia as follows:

8YDZ – 8–9 mol% Y 2O 3-doped ZrO 2: the material is not completely stabilized and decomposes at high application temperatures, see next paragraphs ).

8YSZ – with 8 mol% Y 2O 3 fully stabilized ZrO 2.

4YSZ: with 4 mol% Y 2O 3 partially stabilized ZrO 2, yttria-stabilized zirconia.

Ĭommonly used abbreviations in conjunction with yttria-stabilized zirconia are:

Īlthough 8–9 mol% YSZ is known to not be completely stabilized in the pure cubic YSZ phase up to temperatures above 1000 ☌. Hafnia-stabilized zirconia has about 25% lower thermal conductivity, making it more suitable for thermal barrier applications. Materials related to YSZ include calcia-, magnesia-, ceria- or alumina-stabilized zirconias, or partially stabilized zirconias (PSZ). The resulting doped zirconia materials are termed stabilized zirconias. Stabilization of the cubic polymorph of zirconia over wider range of temperatures is accomplished by substitution of some of the Zr 4+ ions (ionic radius of 0.82 Å, too small for ideal lattice of fluorite characteristic for the cubic zirconia) in the crystal lattice with slightly larger ions, e.g., those of Y 3+ (ionic radius of 0.96 Å).

Obtaining stable sintered zirconia ceramic products is difficult because of the large volume change, about 5%, accompanying the transition from tetragonal to monoclinic. Pure zirconium dioxide undergoes a phase transformation from monoclinic (stable at room temperature) to tetragonal (at about 1173 ☌) and then to cubic (at about 2370 ☌), according to the scheme See also: Zirconium dioxide § Engineering properties

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