Zirconia is a ceramic that is only useful in its stabilized state. As an unstabilized material it tends to crack due to phase changes that occur during changes of temperature. But when Zirconia is partially stabilized with either magnesia or yttria it has excellent mechanical properties at high temperatures and is relatively inert to hostile environments. The ability to retain high strength at elevated temperatures and resist a range of molten metals makes it ideal for use as a crucible material. Compared to other advanced ceramic materials, zirconia has exceptional strength at room temperature. One unusual characteristic of zirconia is that at high temperatures it becomes electrically conductive, hence its use as heating elements. Other properties include good impact strength and good wear resistance.
Zirconia-based ceramics are also used as auxiliaries in welding processes, as tools for wire forming, as oxygen measurement cells, as insulating rings in thermal processes, and as materials for crowns and bridges in the dental industry. These ceramics can produce intricate designs controlling fabrication route, composition, thermal treatment, and final machining.
Please note: the image above is a photo of Zirconia stabilised with Yttria Non-Woven Fabric.