ZrO22

ZrO22 is commonly written as ZrO2, zirconium dioxide, a binary oxide of zirconium. It is a white to off-white powder at room temperature with a very high melting point and notable chemical stability, making it useful in high-temperature and wear-resistant applications. In its pure form, zirconia undergoes polymorphic phase changes: monoclinic below about 1170°C, tetragonal between roughly 1170 and 2370°C, and cubic above about 2370°C. The monoclinic-tetragonal transformation involves a volume change that can cause cracking during cooling, a challenge addressed by stabilizing additives.

Stabilizers such as yttria (Y2O3) or magnesia (MgO) are added to produce stabilized zirconia, retaining tetragonal or cubic phases at room temperature. This stabilization enables transformation toughening, which enhances fracture toughness, hardness, and wear resistance. Stabilized zirconia is commonly referred to as yttria-stabilized zirconia (YSZ) or partially stabilized zirconia (PSZ).

Applications of ZrO2 and stabilized zirconia span a range of high-performance parts. In dentistry and orthopedics, zirconia-based ceramics are used for crowns, restorations, and implants due to their strength and biocompatibility. In engineering, zirconia ceramics serve in cutting tools, bearings, and wear parts. They are also used in thermal barrier coatings for turbines and as electrolytes or supports in solid oxide fuel cells and catalytic systems. In jewelry, cubic zirconia, a gemstone simulant, is composed of zirconia with dopants to achieve desired optical properties.

Note: If ZrO22 was intended to refer to another species or a specific salt or charge state, clarification may be needed.