Английская Википедия:Aluminium oxynitride
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Aluminium oxynitride (marketed under the name ALON by Surmet Corporation[1]) is a transparent ceramic composed of aluminium, oxygen and nitrogen. Aluminium oxynitride is optically transparent (≥ 80%) in the near-ultraviolet, visible, and mid-wave-infrared regions of the electromagnetic spectrum. It is four times as hard as fused silica glass, 85% as hard as sapphire, and nearly 115% as hard as magnesium aluminate spinel. It can be fabricated into transparent windows, plates, domes, rods, tubes, and other forms using conventional ceramic powder processing techniques.Шаблон:Citation needed
Aluminium oxynitride is the hardest polycrystalline transparent ceramic available commercially.[2] Because of its relatively low weight, distinctive optical and mechanical properties, and resistance to oxidation or radiation, it shows promise for applications such as bulletproof, blast-resistant, and optoelectronic windows.[3] Aluminium oxynitride-based armor has been shown to stop multiple armor-piercing projectiles of up to .50 BMG.[4]
Properties
Aluminium oxynitride is resistant to various acids, bases, and water.[5]
Mechanical
Aluminium oxynitride has the following mechanical properties:[2]
- Compressive strength 2.68 GPa
- Flexural strength 0.38–0.7 GPa
- Fracture toughness 2.0 MPa·m1/2
- Knoop hardness 1800 kg/mm2 (0.2 kg load)
- Poisson ratio 0.24
- Shear modulus 135 GPa
- Young's modulus 334 GPa
Thermal and optical
Aluminium oxynitride has the following thermal and optical properties:[6]
- Specific heat 0.781 J/(g·°C)
- Thermal conductivity 12.3 W/(m·°C)
- Thermal expansion coefficient ~4.7Шаблон:E/°C
- Transparency range 200–5000 nm
Applications
Aluminium oxynitride is used for infrared-optical windows, with greater than 80% transparency at wavelengths below about 4 micrometers, dropping to near zero at about 6 micrometers.[7] It has also been demonstrated as an interface passivation layer in some semiconductor-related applications.[8]
Aluminium oxynitride has less than half the weight and thickness of glass-based transparent armor.[9] Aluminium oxynitride armor of Шаблон:Convert thickness is capable of stopping .50 BMG armor-piercing rounds, which can penetrate Шаблон:Convert of traditional glass laminate.[7][10]
In 2005, the United States Air Force began testing aluminium oxynitride-based armor.[11]
Manufacture
Aluminium oxynitride 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%.[12] The fabricated greenware is subjected to heat treatment (densification) at elevated temperatures followed by grinding and polishing to transparency. It can withstand temperatures of about Шаблон:Convert in inert atmospheres. The grinding and polishing substantially improves the impact resistance and other mechanical properties of armor.[6]
Patents
Patents related to aluminium oxynitride include:
- Aluminium oxynitride having improved optical characteristics and method of manufacture TM Hartnett, RL Gentilman Шаблон:US Patent, 1984
- Process for producing polycrystalline cubic aluminium oxynitride JW McCauley Шаблон:US Patent, 1980
- Transparent aluminium oxynitride and method of manufacture RL Gentilman, EA Maguire Шаблон:US Patent, 1985; Шаблон:US Patent, 1988
- Transparent aluminium oxynitride-based ceramic article JP Mathers Шаблон:US Patent, 1993
See also
References
External links
- Processing of Optically Transparent Aluminum Oxynitride
- "Solubility Limits of La and Y in Aluminum Oxynitride (AlON) at 1870°C". Lior Miller and Wayne D. Kaplan. Department of Materials Engineering, Technion, Haifa, Israel, 2006.
- The Influence of Sintering Additives on the Microstructure and Properties of ALON. Yechezkel Ashuach. Master's Thesis, Technion – Israel Institute of Technology, 2003.
Шаблон:Aluminium compounds Шаблон:Authority control
- ↑ Шаблон:Cite patent
- ↑ 2,0 2,1 Mohan Ramisetty et al. Transparent Polycrystalline Spinels Protect and Defend, American Ceramic Society Bulletin, vol.92, 2, 20–24 (2013)
- ↑ Шаблон:Cite web
- ↑ Шаблон:Cite journal
- ↑ Шаблон:Cite journal
- ↑ 6,0 6,1 Joseph M. Wahl et al. Recent Advances in ALON Optical Ceramic, Surmet
- ↑ 7,0 7,1 Шаблон:Cite journal
- ↑ Шаблон:Cite journal
- ↑ Security News (2015-06-03). Optically Clear Aluminium Provides Bulletproof Protection. TSS, 3 June 2015. Retrieved on 2015-07-10 from http://www.tssbulletproof.com/optically-clear-aluminum-provides-bulletproof-protection/ Шаблон:Webarchive.
- ↑ Шаблон:Cite web
- ↑ Шаблон:Cite web
- ↑ Шаблон:Cite journal
