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Zirconium dioxide (ZrO 2), sometimes known as zirconia (not to be confused with zirconium silicate or zircon), is a white crystalline oxide of zirconium.Its most naturally occurring form, with a monoclinic crystalline structure, is the mineral baddeleyite.
Zirconium is relatively abundant in S-type stars, and has been detected in the sun and in meteorites. Lunar rock samples brought back from several Apollo missions to the moon have a high zirconium oxide content relative to terrestrial rocks. [23] EPR spectroscopy has been used in investigations of the unusual 3+ valence state of zirconium.
Zirconium oxide is used due to the fact it exists in several different forms. Zirconium can be monoclinic , tetragonal or cubic in form. Cooling to the monoclinic phase after sintering causes a large volume change, which often causes stress fractures in pure zirconia.
Discovered in 1892, the yellowish monoclinic mineral baddeleyite is a natural form of zirconium oxide. [2] The high melting point of zirconia (2750 °C or 4976 °F) hinders controlled growth of single crystals. However, stabilization of cubic zirconium oxide had been realized early on, with the synthetic product stabilized zirconia introduced ...
Yttria-stabilized zirconia (YSZ) is a ceramic in which the cubic crystal structure of zirconium dioxide is made stable at room temperature by an addition of yttrium oxide. These oxides are commonly called "zirconia" (Zr O 2) and "yttria" (Y 2 O 3), hence the name.
Corrosion resistance of zirconium alloys is enhanced by intentional development of thicker passivation layer of black lustrous zirconium oxide. Nitride coatings might also be used. Whereas there is no consensus on whether zirconium and zirconium alloy have the same oxidation rate, Zircaloys 2 and 4 do behave very similarly in this respect.
Zirconia aluminia (or zirconia toughened alumina), a combination of zirconium oxide and aluminum oxide, is part of a class of composite ceramics called AZ composites. Noted for their mechanical properties, AZ composites are commonly used in structural applications, as cutting tools, and in many medical applications.
Baddeleyite is a rare zirconium oxide mineral (ZrO 2 or zirconia), occurring in a variety of monoclinic prismatic crystal forms. It is transparent to translucent, has high indices of refraction, and ranges from colorless to yellow, green, and dark brown.