Aluminium oxynitride


Aluminium oxynitride or ALON is a ceramic composed of aluminium, oxygen and nitrogen. It is marketed under the name ALON by Surmet Corporation. ALON is optically transparent in the near-ultraviolet, visible and midwave-infrared regions of the electromagnetic spectrum. It is four times harder than fused silica glass, 85% as hard as sapphire, and nearly 15% harder than magnesium aluminate spinel. Since it has a cubic spinel structure, it can be fabricated to transparent windows, plates, domes, rods, tubes and other forms using conventional ceramic powder processing techniques. ALON is the hardest polycrystalline transparent ceramic available commercially. Its combination of optical and mechanical properties makes this material a leading candidate for lightweight high-performance transparent armor applications such as bulletproof and blast-resistant windows and for many military infrared optoelectronics. ALON-based armor has been shown to stop multiple armor-piercing projectiles of up to.50 BMG cal. It is commercially available in sizes as large as monolithic windows.

Properties

;Mechanical
;Thermal and optical
ALON also appears to be radiation-resistant and resistant to damage from various acids, bases, and water.

Applications

In addition to being used as a transparent armor material, ALON is used as infrared-optical windows. As such it has applications as a sensor component, speciality IR domes, windows for laser communications, and in some semiconductor-related applications.

Bulletproof glass

As a transparent armor material, ALON provides a bulletproof product with far less weight and thickness than traditional bulletproof glass. It has been dubbed transparent aluminium after a fictional Star Trek material. thick ALON armor is capable of stopping.50 BMG armor-piercing rounds, which can penetrate of traditional glass laminate.

Military

In 2005, the United States Air Force began testing ALON, "to shield troops".

Manufacture

ALON can be fabricated as windows, plates, domes, rods, tubes and other forms using conventional ceramic powder processing techniques. Its composition can vary slightly: the aluminium content from about 30% to 36%, which has been reported to affect the bulk and shear moduli by only 1–2%.. The fabricated greenware is subjected to heat treatment at elevated temperatures followed by grinding and polishing to transparency. It can withstand temperatures of about 2100 °C in inert atmospheres. The grinding and polishing substantially improves the impact resistance and other mechanical properties of armor.

In popular culture

Aluminum oxynitride is not mentioned in the 1986 film , but "transparent aluminum" became a popular phrase after appearing in the film.
Aluminum oxynitride is mentioned and described in the Jack Reacher novel, Personal by Lee Child, and mentioned by Jimmy Fallon as the material used to create the gyrosphere vehicles' outer protective bubble in the 2015 film Jurassic World.

Patents