Zirconium dioxide (or zircona, ZrO₂), sometimes known as zirconia is a white crystalline oxide of zirconium. It crystallizes in monoclinic, tetragonal or cubic systems. Due to the fact the transformation to monoclinic structure brings a volumetric change, different cations are used to stabilize these crystalline structures, such as magnesium oxide (MgO), calcium oxide (CaO) or yttria oxide (Y₂O₃). There are two options when stabilizing it: totally (totally stabilized zirconia (TSZ) or partially stabilized zircona (PSZ). PSZ process is remarkable, because it prevents the tetragonal phase transformation to monoclinic phase. This is due to its “pre-tension” which leads to an increase of resistance and hardness. The zirconium oxide has achieved a high importance in the past years due to the following properties: extremely fracture resistance, high wear and corrosion resistance, thermal expansion similar to cast iron and low thermal conductivity.