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
Behavior of nuclear fuel during a reactor accident is thought that the surface of the cladding could reach a temperature between 800 and 1400 K, and the cladding will be exposed to steam for some time before water is reintroduced into the reactor to cool the fuel. During this time when the hot cladding is exposed to steam some oxidation of the zirconium will occur to form a zirconium oxide which is more zirconium rich than zirconia. This Zr(O) phase is the α-phase, further oxidation forms zirconia. The longer the cladding is exposed to steam the less ductile it will be. One measure of the ductility is to