YSZ

Yttria-stabilized zirconia (YSZ) is a ceramic in which the crystal structure of zirconium dioxide is made stable at room temperature by an addition of yttrium oxide. These oxides are commonly called "zirconia" (ZrO₂) and "yttria" (Y₂O₃), hence the name.

Pure zirconium dioxide undergoes a phase transformation from monoclinic (stable at room temperature) to tetragonal (at about 1173 °C) and then to cubic (at about 2370 °C), according to the scheme:

monoclinic (1173 °C) ${\displaystyle \leftrightarrow }$ tetragonal (2370 °C) ${\displaystyle \leftrightarrow }$ cubic (2690 °C) ${\displaystyle \leftrightarrow }$ melt

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