Aluminium oxynitride

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"AlON" redirects here. For the aircraft corporation, see Alon.

Aluminium oxynitride
Systematic name	Aluminium oxynitride
Identifiers
Abbreviations	AlON
CAS number
Properties
Molecular formula	(AlN)_x.(Al₂O₃)_1-x, mole fraction 0.30 ≤ x ≤ 0.37
Appearance	White or transparent solid
Density	3.688 g/cm³
Melting point	~2140 °C
Boiling point	? ( Al₂O₃~3000°C)
Solubility in water	insoluble
Structure
Crystal structure	cubic spinel
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Aluminium oxynitride (AlON) is a transparent ceramic composed of aluminium, oxygen and nitrogen. It is marketed under the name ALON and described in U.S. Patent 4,520,116 . The material remains solid up to 1200°C (2200°F), and is harder than glass. When formed and polished as a window, the material currently (2005) costs about US$10 to US$15 per square inch (~ US$20,000/m²).

It is currently the crucial outer layer of experimental transparent armor being considered by the US Air Force for the windows of armored vehicles. Other applications include semiconductors and retail fixtures.

Objects are usually formed from pressed, cast or molded powder. The formed objects are then densified by heating in an oven, and polished until transparent. The polishing substantially improves the armor's impact resistance.^[1]

Transparent aluminum has the unusual distinction of being a real substance whose existence was originally a work of fiction. Before its actual invention, it was referred to in the movie Star Trek IV: The Voyage Home.