Production and Chemical Properties
- Zirconia is produced by calcining zirconium compounds.
- Zirconia has the chemical formula ZrO.
- Its molar mass is 123.218 g/mol.
- Zirconia appears as a white powder.
- Zirconia is chemically unreactive.
- It is slowly attacked by concentrated hydrofluoric acid and sulfuric acid.
- It converts to zirconium carbide when heated with carbon.
- In the presence of chlorine, it converts to zirconium(IV) chloride.
- This conversion is used for the purification of zirconium metal.

Structure
- Zirconia has three phases: monoclinic, tetragonal, and cubic.
- The higher the temperature, the higher the symmetry of the structure.
- The cubic phase can be stabilised by adding oxides of calcium or yttrium.
- Monoclinic zirconia consists of seven-coordinated zirconium centers.
- The mineral tazheranite is cubic and contains Zr, Ti, and Ca.

Engineering Properties
- Zirconia undergoes phase changes from monoclinic to tetragonal to cubic.
- The change in volume during these transitions can cause cracking.
- Stabilised zirconia with dopants like yttria has superior properties.
- Transformation toughening enhances fracture toughness.
- Zirconia has a band gap dependent on its phase and preparation methods.

Uses
- Zirconia is used in the production of hard ceramics.
- It is used in dentistry for dental restorations and prostheses.
- Zirconia is used in oxygen sensors and fuel cell membranes.
- It is a precursor to lead zirconate titanate, a high-κ dielectric.
- Zirconia is used as a thermal barrier coating in engines.

Applications, Properties, and Research
- Zirconium dioxide is used in watch cases, gas tungsten arc welding electrodes, and thermal-barrier coatings for gas-turbine engines.
- It is used in dental ceramics, kitchen knives, and tools.
- Zirconium dioxide is four times harder than stainless steel.
- It undergoes phase transformations during oxidation and exhibits transformation toughening.
- Zirconium dioxide has various industrial and scientific applications, such as catalysts and photocatalysts.
- Research has been conducted on the properties, machinability, and applications of zirconia ceramics.
- Studies have been done on the phase transformation during oxidation of zirconium alloys and the toughening of zirconia through martensitic transformations.
- Rapid prototyping and porcelain fused to zirconia prosthesis have been explored for dental applications.