ALON, also known as transparent aluminium armour is a ceramic alloy made of aluminum oxynitride, a combination of aluminum, oxygen and nitrogen.
ALON is both lighter (about 0.5x) and stronger (> 2x) than the traditional bullet-proof glass; it is resistant to scratches, radiation, various acids and bases.
According to Surmet Corporation, the sole producer of ALON globally, the properties of ALON are as follows:
- Structure: Cubic-spinel
- Density: 3.691 - 3.696 g/cm³
- Refractive index: 1.79
- Form: Polycrystalline
- Melting Point: 2150°C
- Young's Modulus: 323 GPa
- Knoop Hardness: 1850 kg/mm2 (0.2 kg load)
- Fracture Toughness: 2.0 - 2.9 MPa.m½
- Flexure Strength: 380 - 700 MPa
- Thermal Conductivity: 13 W/mK
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Like every other ceramic, ALON starts as a powder which is then molded by heating and baking at high temperature. During this process, the powder liquefies and then quickly cools forming a solid crystalline structure. Additional polishing strengthens the aluminium alloy and also makes it very clear.
ALON is highly applicable as bulletproof glass of automobiles and warships, aerospace.
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