Yttria-stabilized zirconia is known to not be completely stabilized in the pure cubic YSZ phase up to temperatures above 1000 °C (Ref. and publications therein), commonly used abbreviations in conjunction with yttria-stabilized zirconia are: The thermal expansion coefficients depends on the modification of zirconia as follows: By the addition of yttria to pure zirconia (e.g., fully stabilized YSZ) Y ions replace Zr on the cationic sublattice. Thereby, oxygen vacancies are generated due to charge neutrality: formula_4 with formula_5, meaning two Y ions generate one vacancy on the anionic sublattice. This facilitates moderate conductivity of yttrium stabilized zirconia for O ions (and thus
Zirconium dioxide the basis for the purification of zirconium metal and is analogous to the Kroll process. Zirconium dioxide is one of the most studied ceramic materials. ZrO adopts a monoclinic crystal structure at room temperature and transitions to tetragonal and cubic at higher temperatures. The change of volume caused by the structure transitions from tetragonal to monoclinic to cubic induces large stresses, causing it to crack upon cooling from high temperatures. When the zirconia is blended with some other oxides, the tetragonal and/or cubic phases are stabilized. Effective dopants include magnesium oxide (MgO), yttrium oxide (YO, yttria), calcium oxide (CaO), and