Zirconium dioxide



Zirconia redirects here. For the Sailor Moon character, see Dead Moon Circus.
Thermodynamic data
IUPAC name Zirconium dioxide; Zirconium(IV) oxide
Other names Zirconia; Baddeleyite
Identifiers
CAS number 1314-23-4
Properties
Molecular formula ZrO2
Molar mass 123.22 g/mol
Appearance white solid
Density 5.89 g/cm³, solid
Melting point

2715 °C

Boiling point

°C

Solubility in water Insoluble
Thermochemistry
Std enthalpy of
formation ΔfHo298 		−1080 kJ/mol
Standard molar
entropy So298 		50.3 J.K−1.mol−1
Hazards
EU classification not listed
Related Compounds
Other anions Zirconium disulfide
Other cations Titanium dioxide; Hafnium dioxide
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references

Zirconium dioxide (ZrO2), sometimes known as zirconia, is a white crystalline diamond simulant.

Ceramic and engineering properties

Zirconium dioxide is one of the most studied cerium oxide (Ce2O3), amongst others.

Zirconia is very useful in its 'stabilized' state. In some cases, the tetragonal phase can be metastable. If sufficient quantities of the metastable tetragonal phase is present, then an applied stress, magnified by the tetragonal zirconia polycrystaline or TZP, which is indicative of polycrystalline zirconia composed of only the metastable tetragonal phase.

The Carnot heat engine). As of 2004, a great deal of research is ongoing to improve the quality and durability of these coatings. It is used as a electroceramics.

Zirconia is sometimes classified as a semiconductor and tends to become more conductive at higher temperatures. Zirconia starts out with a very high resistance at room temperature, greater than 1 trillion ohm-cm. As the temperature increases it has less than 20,000 ohm-cm at 500 degrees Celsius, to having less than 1,000 ohm-cm of resistance at 1,000 degrees Celsius. It loses nearly all of its resistance around 2,000 degrees Celsius, and becomes a very good conductor. The ZrO2 bandgap is dependent on the phase (cubic, tetragonal, monoclinic, or amorphous) and preparation methods, with typical estimates from 5-7 eV.[1]

This material is also used in the manufacture of subframes for the construction of dental restorations such as crowns and bridges which are then veneered with a conventional feldspathic porcelain.

Zirconium dioxide can occur as a white powder which possesses both limelight.

Zirconia is also an important dielectric material that is being investigated for potential applications as an insulator in transistors in future nanoelectronic devices.

Diamond Substitute

Single crystals of the Zircon is actually the mineral name for naturally occurring Zirconium silicate (ZrSiO4). Its transparent form is also used as a gemstone, and its opaque form as a refractory.

Patents

On August 7, 2006, Apple Computer filed a patent for using zirconia as casing for mobile devices. Future iPods likely will contain radios for Bluetooth and wide area wireless. Using zirconia rather than steel or aluminum for its radio transparency characteristics enables antennas to be hidden internally in the device. Additionally, some iPods with plastic fronts have been known to scratch easily.[2]

References

  1. ^ J.P. Chang, Y-S. Lin, and K. Chu, "Rapid thermal chemical vapor deposition of zirconium oxide for metal-oxide-semiconductor field effect transistor application," J. Vac. Sci. Technol. B 19„5…, pp. 1782-1787, (2001)
  2. ^ "Apple seeks patent on radio-transparent zirconia CE casings", Apple Insider. 


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This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Zirconium_dioxide". A list of authors is available in Wikipedia.